How it works
A factory reset returns supported software and settings to a defined starting state. Its exact effect depends on the device and selected option: some procedures retain personal files, while others remove user accounts and installed applications. A reset is different from restarting and from restoring one configuration backup. It may resolve a damaged setup, but cannot repair a worn battery, broken connector or failing storage drive.
Before resetting, distinguish your goal: troubleshooting, handing the device to another person or retiring it. Those goals require different preparation. A cloud account, activation lock or organisation management can remain associated with equipment even after local data is removed. Likewise, files already synchronised to cloud storage are not necessarily deleted there when the device is reset. Follow the relevant account-removal and secure-erasure procedure for the exact model.
Practical checks
Make and verify a backup, check access to passwords and recovery keys, and record essential applications or subscriptions. Read which data the selected reset option preserves before confirming it. Keep the required power supply connected and allow the procedure to finish without an unnecessary forced restart. After troubleshooting, test the original fault before reinstalling everything. For a transfer, verify the device reaches its intended setup state without exposing your account or files.