It's a barre - meaning that one finger, here the index finger (not always though) is across all six strings. That doesn't mean that all six need to be pressed down onto the fingerboard - strings 5, 4 and 3 are already pressed down on frets 2 and 3.
So, it's called a barre chord - and as such is movable in its shape up and down the fingerboard, making many different major (in this case) chords.
As I say, the index finger doesn't need to press down hard on all six strings, as only 6, 1 and 2 are actually affected by the barre. It's one of the bête noire chords for beginners, but once you've mastered the concept, will lead you into a whole new world of chord shapes and keys. I've only ever had one student who played them successfully the first time they tried!