Something comes on my phone about my account is being used on another device

Read the section titled, "The first time that you sign in with your Apple ID on a new device" by clicking on the link for the support article Two-factor authentication for Apple ID - Apple Support

You get that warning if another device using your ID has been activated. It could be a security issue or it could be something innocent. I have seen that notice when I have turned on a device I haven't used for a month or two.

Read this document if you think your Apple ID has been compromised. --> If you think your Apple ID has been compromised - Apple Support

For iOS 15 or earlier, if you want to see if anyone else has access to your device or accounts, click here --> See who has access to your iPhone or iPad - Apple Support

For iOS 16 or later see how Safety Check on iPhone works to keep you safe. How Safety Check on iPhone works to keep you safe - Apple Support

Related materials:

Personal Safety User Guide

Personal Safety User Guide - Apple Support

> open the Table of Contents

A document with general information about security and your Apple ID --> Security and your Apple ID - Apple Support

Contact Apple for help with Apple ID account security by clicking on this link --> Contact Apple for help with Apple ID account security - Apple Support "This article provides country-specific Apple Support contact information for customers seeking help with their Apple ID password or other security-related issues."

See the support article: View and remove your devices that are associated with Apple ID purchases - Apple Support - What this is saying is for certain actions such as turning on Match, Apple Music, Family Sharing, automatic downloads, or re-downloading of past purchases there is a 90 day waiting period between associating [using] a computer or mobile device with a new Apple ID . There is no wait for making new purchases.

"When you try to associate a device that was previously associated, you

might notice a message that says, "This device is associated with

another Apple ID. You cannot associate this device with another Apple ID

for [number] days." You might need to wait up to 90 days to associate

the device with a different Apple ID."