If you no longer wish to display a custom field on your application form, you can archive the field. By archiving you will maintain all of the historical information previously submitted for the form.

1. Click Setup > Memberships > Types.

2. 

3. For the desired membership type, click the    icon in the Actions column.
4. Scroll to the Membership Application Custom Fields section.
5. Click the  for the custom field you wish to archive. 
6. Click Edit. 

   

7. Tick the Archived check-box.
8. Click Done.