Take 20?

Is there a way to take 20 on a roll in FG?

Sure... "I'm taking 20, do I xxx?"

Or do you mean to automate it? Sure, two ways I can think of;
1) put a 20 in the modifier box and roll a 1d0
2) turn on manual die rolling and enter a 20

Yes, I mean automate it, so as to add in all the modifiers.

The only times I have played a game where you could “take 20”, it was only with skills. So wouldn’t it be easier to just say “I take 20 on xxxxx skill, with a +5, so thats 25” and the gm adjudicates. Why the need to roll?

The character might have effects that affect skill use, so I can see where in some situations it might be easier to roll it.

I’d just roll the skill normally to see what the modifiers are and then add that to 20.

Yeah, I do the same for oddball passive skill checks. It's one of the few times I'll actually roll off the party sheet.