Key vs capo position

When the key is given with a capo position this will correspond to a chord form that you can read on the 1st column. The capo helps you play in that key without having all the chords barred. For example if you are playing a song in an A chord form scale position (A position) with a capo on the 1st fret, this is a song in B♭ key. You make it easier on yourself by playing the B♭ as an open string A with the bar done by the capo. You can play the chord form A as and E form chord by barring on the 5th fret up from the capo, that's the musician's choice. The capo makes it easier for you to play with other instruments and singers. If the song you are playing is in C and the singer has a high voice you may have to play it in D. Putting the capo on the 2nd fret allows you to keep the same chord form sequence and play in the D key to match the singer.