For most political campaigns, there are strict rules to how much a donor can donate. For this reason, Donorbox provides users with the ability to set a maximum donation amount.
Log into your Donorbox account and click the "Edit Form" link next to your donation form.
Go to the Amounts tab of the form editor. Click on the link that says "+ Enforce max donation amount"
A text box will show up. Just input the max donation amount that you want to set. Click Save when you're done.
Once enabled, if a donor wants to donate more than the maximum amount allowed, an error message will be shown on the first step of the donation form.