For some campaigns (such as 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 icon next to your donation form.
Click the 'Amounts' link under the 'Your Donation Form' header.
Click the 'Enforce max donation amount' toggle and enter your maximum donation amount.
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.