Upvote:6
This answer assumes that your parents are in the United States in B-2 status, and they want to extend their B-2 status filing form I-539. The web page for that form links to a page concerning online filing, which gives the qualifying conditions for filing online:
Conditions to File Form I-539 Online
You may apply online to extend or change your nonimmigrant status if you meet the following conditions.
You are applying:
- As a single applicant;
- Without co-applicants; and
- You will not require legal or accredited representation at any point in your request.
Since your parents are applying together, they cannot use the online application. Instead, they should use the paper application. They will need to fill out two I-539 forms, indicating on each in question 5b that two people are applying together.
I suppose it would be possible to apply separately online, as you suggest, but it's probably better to keep the applications together by using the paper form. This will reduce the chance of the officer making the decision overlooking something, and it should reduce the chance of achieving different results.