Perform the following steps to create a Region picklist field:

  1. Go to Setup, in the Quick Find box, search for Usersand select Fields option under the Users.
  2. Go to the User Custom Fields section and click New.
  3. Select Picklist as Data Type and click Next.
  4. Enter Region as a Field Lable.
  5. Select Enter values, with each value separated by a new line option under Values, and add picklist values for the region and click Next.
  6. Mark the profiles as Visible to which you want to grant edit access to this field via field-level security and click Next.
  7. Click Save.