Enabling Team Drive Creation:

Google Domain Admins can decided if they want to allow users to create Team Drives.  This setting can be accessed by logging into the G Admin Council and accessing: Apps > G Suite > Settings for Drive and Docs>Sharing Settings and selecting/deselecting the checkbox next to Team Drive Creation.  

Migrating Files: 

It can also be decided if user can or cannot migrate files to a Team Drive.  This setting can be accessed at Apps > G Suite > Settings for Drive and Docs>Migration Settings

Managing Existing Team Drives:

Existing Team Drives can also be managed by Google Domain Admins by accessing Apps > G Suite > Settings for Drive and Docs>Manage Team Drives