Cash app Bitcoin is their department that deals with Bitcoin stuff. It is a custodial wallet, meaning they ultimately have control of your funds. You can take it off the platform, but Until you do, they have control over your funds.

For taking payments, maybe look into a wallet like Blue Wallet, which will help with on-chain and maybe look into something like Zeus that will help with lightning. (Although if you're completely new to Bitcoin, maybe avoid lightning for now because it's a whole nother rabbit hole.)

I would avoid custodians, wallets like wallet of Satoshi, cash app, Anything that does not give you access to your private keys.

More than happy to answer other specific questions but off the top of my head in a pre-caffeinated state and this is about all I'm coming up with it the moment.