I've searched on YouTube and asked fellow Samsung users how to use their phone to charge another phone and nothing. So I decided to post this and ask fellow users from around the world.
The other phone must be wireless charging compatible. On your Note 10 just scroll down to your notification panel and turn on the Wireless Powershare toggle and there you go.
What @KnightRalph316 is describing is a way to charge another wireless charging capable device with your Note 10 Plus, but if you're asking about charging the Note with another phone (so the other way around), that other phone must be a Wireless Power Share enabled device too.