The 'Type' may be inactive in code tables, to activate them:
  1. Select the Administration administration
  2. Click Code Tables.
  3.  Choose the Category "Membership"
  4.  Click Membership types
  5.  Click the dropdown next to the type and click Edit. 
  6. Unmark the box "Inactive"

Your membership level may not have types assigned to it:
  1. Select the Memberships tab
  2. Click your the name of your membership in question.
  3. Click the "Terms and levels" tab.
  4. Highlight the level in question and click "Edit Types"
  5. Add the membership types that you need.