Is someone screen mirroring my phone
How can I find out if my boyfriend is screen mirroring my iPhone or is watching my phone from their phone without me knowing?
Check your device list to see if there is a device signed in that you don't recognize. You can remove the device using the steps in the article below. As a precaution, change your password.
Apple ID device list -Check to see where you‘re signed in.
What to do after you change your Apple ID or password - Apple Support I suggest doing this before you change your Apple ID or password.