How do I make a Registration Fee mandatory?

From Memberships, select Registration Fees & Forms.

Click on Forms and then My Forms.This displays the list of your Registration Forms.

Click on the form name you wish to use from the Form Name column. This opens up the Registration form.

Select the Registration Fees and Merchandise tab.

On the line that contains the fee you want to make mandatory, click the checkbox in the Mandatory field.

Click Save.