Am I able to create a variable amount on my form?

i'd like to create a donations form that has an empty field so users can put in their own donation amount.  How can I do this?

You can change the Payment Type in the Payment Settings in order to achieve this, here's how:

In the Form Builder, select the payment field and then click the "Payment Settings" button. In the Payment Integration, you will see the "Payment Type". Please change it to "User Defined Amount" or "Collect Donations".

When you are done, click the "Continue" button and save the form.

Hope that helps. Thank you.