How to transfer installed apps from one account to another
There's currently no way to do this. Free apps can be re-downloaded under the appropriate account, of course, but Google has no provision for moving paid apps (or free ones, in bulk) from one account to another. The Google Play support page has their official stance on this:


  At this time, it's not possible to transfer apps from one account to
  another.
  
  Some developers are willing to issue refunds for purchases on old
  accounts if you repurchase the app(s) using a new account. You can
  always reach out to the developer of an app, and you can find their
  contact information by following these steps: 
  
  
  Visit Google Play and
  select the app in question 
  On the app's description page, scroll down
  to the Developer section 
  Find either an email address, phone number or
  website listed.