You must disable "Find my iPhone" feature before you do the reset. SIM doesn't matter. A good reference for "clean" reset for the purposes of reselling/trading phones is here:I’m about to sell my X to a coworker, does it matter whether I remove the sim card or leave it in when doing the factory reset?
It’s habit of mine always log out of my iCloud account before factory resetting. By logging out of iCloud that disables find my iPhone correct?