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Will it only depend on my home country of which I have the passport?
As a general rule your country of citizenship indicated by your passport is the single most important factor in where you can and can't travel without getting a visa in advance.
There are exceptions to this, for example if you have a Long term visa or Uniform format residence permit from any country in the Schengen area (e.g. france) you can make short visits to any country in the Schengen area without a visit Visa. Unfortunately for you the UK is not in the Schengen area.
The UK does exempt holders of (among other things) "a common format residence permit issued by an European Economic Area (EEA) country or Switzerland" from it's transit visa rules under some circumstances but it doesn't exempt them from visitor visa requirements.
Will it depend on from which country I am entering UK?
That is generally not relevant. The only exception i'm aware of is the "British Irish visa scheme" which allows some holders of Irish visas to travel on to the UK without getting an additional visa and vice-versa.
What kind of document/visa is required?
The UK simplified their visitor visa scheme some time ago, and most visitor visas were merged into the "Standard visitor visa". However some types of visit still require specific visas (and some activities are not permitted on visitor visas at all).
https://www.gov.uk/browse/visas-immigration/tourist-short-stay-visas
There are a bunch of questions on this site answered by far more qualified people than me on te finer points of the application process.