If you do not want a custom additional detail field to be displayed when adding a new donor, you can inactivate it or delete it. However, you cannot delete an additional detail field that has already been used to record donor information.
At the top of your dashboard, click the module access icon > Administration > Finance > Donations to open the Donations page.
In the top right, click the Additional Fields button.
Click Edit beside the custom additional detail field you want to edit, select the Inactive status, and then click the Update button. Custom additional detail fields that are inactivated are moved under the Inactive fields list.
Click Delete beside the custom additional detail field you want to delete.
For more information, watch this-