Before resetting a phone, make a current backup and verify that it includes the information you want to keep. Check photos, contacts, messages, notes, and any app-specific data. Transfer authenticator accounts, banking access, and work information using their official instructions. Make sure you can sign in to your important accounts from another device, since the old phone may be needed for verification during the move.
Remove payment cards and sign out of accounts according to the platform's instructions. If the phone has a device-finding or activation-lock feature, turn it off or remove the device from your account so the next owner is not blocked. Take out a physical SIM card and, if applicable, address the eSIM with your carrier. The correct steps vary by operating system and service, so check current guidance for your specific model.
Use the built-in erase or factory reset option in the phone's settings rather than simply deleting apps and files one by one. Keep the device connected to power until the reset is complete, then confirm it displays the initial setup screen. Do not sign back in after erasing it. Clean the exterior gently, gather any accessories you promised, and keep a record of the handoff. These steps help protect your data and make setup easier for the next owner.