How to tell what network my btc is on?

I need to transfer btc to someone. I have my BTC in cakewallet. My question is how do i make sure those BTC are on the bitcoin network so they wont dissapear when i sent them over?

You’re using Cake Wallet, so your Bitcoin is on the mainnet.

If you’re still not sure, just have a look how your addresses start (Because the testnet uses slightly different address format to avoid confusion with main Bitcoin addresses):
All bitcoin testnet addresses begin with an m or n, so if your addresses start different (e.g. bc1) then you’re ready to go.

Keep in mind that the testnet has no value and is only used for testing and that the mainnet has has real cash value.