Using a capo
Hello! I'm about two months into guitar playing. I've been using a capo to help change the key of different songs so I can sing along, but I'm having trouble understanding exactly how a capo works ... If, for example, I add a capo to the 3rd fret of a song that's normally played without a capo (e.g., wish you were here), do I then need to change the chord shapes that I learned? Or can I just add a capo to whichever fret and play the same chord shapes? I feel like I'm ear blind and can't tell whether the guitar sounds bad. I'm hyper-focused on my voice
I hope this isn't too silly of a question. I've been watching videos on music theory but I still haven't fully grasped it. Thanks in advance!
Edit: wow, thank you all SO much for your incredible (and fast!) replies!!