can not update an app

You are welcome. If the applications that need updating are Apple applications that came with the computer, try going to the App Store Purchases tab or click on your profile and then go to Purchases to see if there is an option to accept the applications with your Apple ID. If that doesn't work, you can delete the applications and download them with your Apple ID. The applications are free. You may have to sign out of the App Store, restart the computer, and sign back in to download new copies.

Purchase History Review

Did you or someone else purchase these apps using their Apple ID and not your Apple ID? Or did you buy your device second-hand, and the apps belonged to the seller?

To update an app you must have acquired the app using your Apple ID to log into the iTunes App Store. You cannot transfer items acquired under one Apple ID to another Apple ID. Only Apple is able to do that.

Contacting Apple Customer and Support Service

1. Apple Store Customer Service at 1-800-676-2775 or visit online Help for more information.
2. Primary support help at Contact Support.
3. To contact product and tech support:  Contacting Apple for support and service including international calling numbers.
4. Starting  an  online  chat  with  Apple  Support.
5. Apple  Support  using  Twitter.
6. For Mac App Store: Apple - Support - Mac App Store.
7. For iTunes: Apple - Support - iTunes.

Check your purchases history to see if you downloaded the app.

Purchase History Review.  

It may not have been your Apple ID. So, this might be your problem. See What to do when the Mac App Store shows a different Apple ID for software updates https://www.macworld.com/article/3267709/mac-app-store-apple-id.html. This document refers to a prior owner, not to you.

Regardless, If an app is purchased/downloaded using one Apple ID, then you can't update it with a second Apple ID. The app is inextricably linked to the first Apple ID. You'll have to delete it and purchase/download it again with the second Apple ID.