Pick a song you intend to play. Play it. It’s too low for your vocal range. Put a capo on. Play again. Still too low? Move capo up… sound good? Good…. just play the chords by their name. IOW, if you play an A chord the first time, then simply play a a chord again…. —as though you were playing without a capo—
Or… as likes to say….. “Same as it ever was”….
Capo on = same chord locations and you “think” as though you are playing open position…. but technically the chords have changed names…. perhaps from A D E to B E F#
But you just play and pretend like you are still playing open chords. whatever the music says you play those shapes.
An alternative method of using a capo is to use bar chords.