unable to update Pages or Keynote on new MacBook Pro 2020

• Click on the desktop to activate the Finder
• go to the Go menu in the menu bar and select Applications
• right click Keynote application and select Move to Trash
• go to Finder > Empty trash
• open the the App Store application in the applications folder, sign in with your Apple ID, type " Keynote" in the search box then click the download button for Keynote

That means they were originally purchased using another Apple ID. The simplest solution is delete the app from the applications folder and download it again (its a free app) from the App Store.