The AdvologixPM Billing Edit does not use a standard page layout and therefore cannot be customized to the same extent as standard page layouts.
Organizations may however add custom fields to the "Additional Information" section of the Billing Edit, as illustrated below.
Example
The following steps illustrate how to quickly add and remove fields from the Billing Edit's "Additional Information" section. This is the only area of the Billing Edit that can be customized.
Navigate to Setup
Click on your name then choose Setup.
Navigate to Objects
Under App Setup
Click Create then choose Objects
Navigate to the Billing Object
Select ‘Billing’ in the list.
Edit the Billing Field Set
Locate to the Field Set called fieldSet_Billing then click the Edit link on the left.
Choose Additional Billing Fields
Click, Drag and Drop the desired field into the lower 'In The Fields Set' section.
Save Your Work
Additional Considerations
These steps have added additional fields to the Billing create/edit page ONLY.
You may also wish to add these fields to other Billing Page layouts using the standard platform page layout capabilities.