Safepal
Go to Safepal offcial website, check their FAQ or contact their customer support. Ask them how to do coin control for bitcoin with the wallet. If you do Google search you will be able to find many articles available online about anything on the internet. Use those resources to learn coin control.
Your keyword is Coin Control. How to do it with Electrum is nicely shown by bitmover already.
From the look of things, Safepal is a close source wallet although they didn't state it in the site but from the articles I read and my own understanding, it is a custodian wallet.
Safepal is a custodial wallet? I did not check my desk yet but as far as I know I have one safepal hardware wallet. A hardware wallet is none custodial, same as Ledger, Trazor. Even desktop wallet like Electrum. This is safepal official website:
https://www.safepal.com/en/From the look of things, Safepal is a close source wallet although they didn't state it in the site but from the articles I read and my own understanding, it is a custodian wallet.
You are right that Safepal is close-source,
I was talking about the information about how to use the wallet. If it has coin control, then I think their manual will have some type of instructions. Those bloggers and crypto writers who review wallet they will have some kind of tutorial tll.