Does God have a form as seen by John the Apostle?

God does have a form of a human, but because of our sins, we are spiritually blind because he Himself said in Isaiah 59 that His face is hidden from us because of our sins. This tells us if it were not for our sins then we all would be able to see Him.

Why would God our Father want to hide His face from His children? I don't think so. Adam saw Him before he sinned in the garden of Eden. I myself went to Heaven 8 times, seen Christ 13 times and the Father 6 times in the past 5 years. I wrote a book called "8 Trips to Heaven" it's a great book. I explained all that I saw in those 8 trips I made to heaven.

John 1:18

"No man has seen God at any time; the only-begotten god who is at the Father’s side is the one who has explained Him."

It may be possible, however that the prophets may have seen aspects of him such as found in Ezekiel 1:26-28

"Above the expanse that was over their heads was what looked like a sapphire stone, and it resembled a throne. Sitting on the throne up above was someone whose appearance resembled that of a human. I saw something glowing like electrum that was like a fire radiating from what appeared to be his waist and upward; and from his waist down, I saw something that resembled fire. There was a brilliance all around him like that of a rainbow in a cloud on a rainy day. That was how the surrounding brilliant light appeared. It was like the appearance of the glory of Jehovah. When I saw it, I fell facedown and began to hear the voice of someone speaking."

Daniel 7:9

“I kept watching until thrones were set in place and the Ancient of Days sat down His clothing was white like snow, and the hair of his head was like clean wool. His throne was flames of fire; its wheels were a burning fire."

An explanation of those visions can be found in Insight from the Scriptures VII

"these descriptions employ metaphors and similes, likening Jehovah’s appearance to things known to humans—jewels, fire, rainbow. He is even described as though he had certain human features. While some scholars make a considerable issue out of what they call the anthropomorphological expressions found in the Bible—as references to God’s “eyes,” “ears,” “face” (1Pe 3:12), “arm” (Eze 20:33), “right hand” (Ex 15:6), and so forth—it is obvious that such expressions are necessary for the description to be humanly comprehensible. For Jehovah God to set down for us a description of himself in spirit terms would be like supplying advanced algebraic equations to persons having only the most elementary knowledge of mathematics, or trying to explain colors to a person born blind.—Job 37:23, 24. The so-called anthropomorphism's, therefore, are never to be taken literally, any more than other metaphoric references to God as a “sun,” “shield,” or “Rock.”

So drawing from that I am unsure whether John saw a physical form or was trying to relate in human terms what he saw. It is pretty hard to describe something to others when they have absolutely no knowledge of what it looks like or in this case relating a vision when there are no words to properly explain what you saw. Instead you try to use describing words to relate it to others. It's sort of like describing the wind. You can't see it, but you can describe things about it to make it understandable.

Moses "saw" God too. but then he left this warning to the people of Israel at Deuteronomy 4:15-18

“Therefore, watch yourselves closely—since you did not see any form on the day Jehovah spoke to you in Ho′reb out of the middle of the fire— that you may not act corruptly by making for yourselves any carved image having the form of any symbol, the representation of male or female, the representation of any animal on the earth or the representation of any bird that flies in the sky, the representation of anything creeping on the ground or the representation of any fish in the waters under the earth.

Moses said that after he had seen God in Exodus 24:9-11

Moses and Aaron, Na′dab and A·bi′hu, and 70 of the elders of Israel went up, and they saw the God of Israel. Under his feet was what seemed like a sapphire pavement, and it was as pure as the heavens themselves He did not harm the distinguished men of Israel, and they saw a vision of the true God and ate and drank.

As we do not have the proper information we then cannot make a conclusion. That is something we will have to ask God later I guess.

Short answer Yes.

Biblical Evidence

• God created man in his own image: Gen. 1:27
• God created man, in the likeness of God made he him: Gen. 5:1 .
• in the image of God made he man: Gen. 9:6 .
• Lord went his way, as soon as he had left communing: Gen. 18:33 .
• I have seen God face to face: Gen. 32:30 .
• they saw the God of Israel: and there was under his feet: Ex. 24:10 .
• written with the finger of God: Ex. 31:18 . ( Deut. 9:10 . )
• Lord spake unto Moses face to face: Ex. 33:11 .
• thou shalt see my back parts: but my face shall not be seen: Ex. 33:23 .
• With him will I speak mouth to mouth: Num. 12:8 .
• a voice from heaven, saying, This is my beloved Son: Matt. 3:17 .
• every word that proceedeth out of the mouth of God: Matt. 4:4 .
• a voice out of the cloud: Matt. 17:5 .
• for a spirit hath not flesh and bones, as ye see me have: Luke 24:39
• he that hath seen me hath seen the Father: John 14:9 .
• the Son of man standing on the right hand of God: Acts 7:56 .
• predestinate to be conformed to the image of his Son: Rom. 8:29 .
• Christ, who is the image of God: 2 Cor. 4:4 .
• Who, being in the form of God: Philip. 2:6
• our vile body … fashioned like unto his glorious body: Philip. 3:21
• Who is the image of the invisible God: Col. 1:15 .
• the express image of his person: Heb. 1:3 .
• men, which are made after the similitude of God: James 3:9 .
• when he shall appear, we shall be like him: 1 Jn. 3:2 .
• they shall see his face: Rev. 22:4 .

God does not have a form that is like a human. God is Spirit (John 4:24).

Exodus 33:20 tells us, “You cannot see my face, for no one may see me and live.” As sinful human beings, we are incapable of seeing God in all His glory. His appearance is utterly unimaginable and too glorious to be safely perceived by sinful man. John did not see God. What he had was a heavenly vision.

When God said, “Let us make man in our image, in our likeness,” (Genesis 1:26) He was not making any reference to flesh and blood. “Male and female he created them” (Genesis 1:27). The creation account in Genesis chapter 2 provides the background and basis for human gender distinctions, sexuality, and even marriage. Clearly, this “likeness” has nothing to do with physical bodies.

Because God is spirit He exists without a body. The image of God (Latin: imago dei) refers to the immaterial part of humanity. It sets human beings apart from the animal world, fits them for the dominion God intended them to have over the earth (Genesis 1:28), and enables them to commune with their Maker. It is a likeness mentally, morally, and socially.

Mentally, humanity was created as a rational, volitional agent. In other words, human beings can reason and choose. This is a reflection of God’s intellect and freedom. Anytime someone invents a machine, writes a book, paints a landscape, enjoys a symphony, calculates a sum, or names a pet, he or she is proclaiming the fact that we are made in God’s image.

Morally, humanity was created in righteousness and perfect innocence, a reflection of God’s holiness. God saw all He had made (humanity included) and called it “very good” (Genesis 1:31). Our conscience or “moral compass” is a vestige of that original state. Whenever someone writes a law, recoils from evil, praises good behaviour, or feels guilty, he or she is confirming the fact that we are made in God’s own image.

Socially, humanity was created for fellowship. This reflects God’s triune nature and His love. In Eden, humanity’s primary relationship was with God (Genesis 3:8 implies fellowship with God), and God made the first woman because “it is not good for the man to be alone” (Genesis 2:18). Every time someone marries, makes a friend, hugs a child, or attends church, he or she is demonstrating the fact that we are made in the likeness of God. https://www.gotquestions.org/image-of-God.html

The Bible describes God appearing to people on various occasions. These instances should not be understood as describing exactly what God looks like, but rather as God revealing Himself to us in a way that we can understand. What God looks like is beyond our capability of understanding and describing. God gives glimpses of what He looks like to teach us truths about Himself, not necessarily so that we can have an image of Him in our minds. Two passages that powerfully describe God’s amazing appearance are Ezekiel 1:26-28 and Revelation 1:14-16.

When Jesus is described (Revelation 5:1-7) as a slain Lamb with seven horns and seven eyes are we to conclude that this is literally what Jesus, the Lamb of God, looks like? How could this Lamb literally take hold of a literal scroll? In its mouth? Hardly! This vision is a representation, a symbol, and is not literal.

Let’s go back to Revelation 4:2-3. John was granted a vision of “someone” sitting on a throne, but that “someone” appeared like brilliant and glorious precious gems. John had to use symbolic language to describe that for which human language has no words; i.e., “what appeared like,” “like the appearance,” “he looked like,” etc. The use of words such as “right hand” does not mean God has a physical hand. John did not see God as a human with a human body.

From the visions of the throne in heaven in Revelation 4:2 and 5:1 we conclude that John’s description is not to be taken as a literal description of either God or of the Lamb.