At Setup, Sync and Learn your security and privacy is always important. It’s always good housekeeping to change your password at least once or twice every year. It does seem straight forward, but at times you might find yourself getting numerous notifications on your devices to sign-in again. So to make it a little less stressful for you here’s a short list of what to check after you’ve changed your Apple ID or Password…
Update your Apple ID and password on your iPhone, iPad, iPod touch, Mac, and PC.
iPhone, iPad, and iPod touch
Go to Settings > (your name) > iTunes & App Store.
If you're signed out, enter your updated Apple ID and password.
If you're signed in with your previous Apple ID, tap your Apple ID, then tap Sign Out. Then enter your updated Apple ID and password.
Mac with OS X or Windows PC
Go to Apple’s website.
Click on the Shopping Bag icon, then click Account.
In the Account Settings section, click Apple ID and password.
Enter your updated Apple ID and password.
You will also have to update your login details by Signing Out then Signing back in to other apps such as FaceTime, iCloud, Find my iPhone, etc.
Click on this link to see a full list and instructions from Apple Support on what to do…