for as long as
(Twitter will allow employees to work from home for as long as they want.) ve as long as
(Twitter will allow employees to work from home as long as they want.) arasındaki fark nedir?Sadece örnek cümleler vermekten çekinmeyin.

The use of "for" in this sentence is to address that you are talking about the time frame they can do or will be doing the action of the sentence.
I would suggest using "for" just simply because it sounds better, as well as it is a good habit to get into.
In this sentence "for" is not necessary for the sentence to still make sense grammatically, but if you were to say "I am going to study an hour" instead of "I am going to study for an hour" we cannot tell if you are studying for an hour or if you are taking the hour as a time unit and just studying it.
"for" is used in the sentence to redirect the subject to how long the action will be done if that makes sense.