Why to use a capo?
A capo gives you more options to play more songs. It can make the chords easier to play while sounding the same. It can also be the only way to play certain songs authentically e.g. Wonderwall requires a capo at 2nd fret to be at the correct pitch to the original recording.
For singers, if a song uses a capo in the original recording - singers can choose to put the capo at a lower fret to make it at a lower pitch, which is typically easier to sing.
How to use a capo
Songs in the key of G or G#
Song uses chords G and C or G# and C#
Solution; Use a capo at 3rd fret and play the chords E major and A major instead, this will sound the same.
Song examples; Love Me Do by The Beatles, Common People by Pulp
Songs in the key of E major, but uses barre chords
Solution; capo at 2nd fret and use chords in the key of D major using ‘transpose’ feature on a chord sheet website.
Song example; Sit Down by the band James.
Song is in the key of C, but uses the F barre chord
Solution; Capo at 5th fret and play chords in the key of G to sound the same!
Song example; Hallelujah by Jeff Buckley/ Leonard Cohen
Song is in the key of B major, requiring to player to use many barre chords
Solution; capo at 2nd fret and transpose those chords to the key of A major, which uses fewer or no barre chords
Song example; Born in the USA by Bruce Springsteen