Buying through P2P

Whats up! I am new to this. I'm making an attempt to buy by way of P2P and the seller is asking for my ID and photograph of it. I asked why and he didn’t reply. I requested canceling the order because it’s been over 15 min, and now I get notified that my completion price might be affected. Is it necessary to ship personal info to sellers? Like I don’t assume it make sense to keep sending my private info to random strangers. How this work?