Hello,
You can copy the screen and bring up the screen designer for the page. (Either through right-clicking the page and selecting customizing and going through the steps or going to Customize -> Screens and using the copy function). Find the Invoices grid on the left hand side of the screen. It should be at the top. Click 'Edit' on the grid and go to Step 2. Here you can add fields. Select Field, choose the field you want to add and click 'Insert Column'. Save your work by clicking Finish on the pop-up and Publish on the screen designer.
Check out our Help Center with customization videos. You would be looking for the Introduction to the Customization Screen.
- Greg
Greg Bilous
Community Support Specialist
Method Integration
g.bilous@method.me
Toll Free: 1.888.925.6238
Local and overseas: 416.847.0400 ex.756
Fax: 416.640.6027