To do this task
Open the type of form you want to customize.
For example, to open the invoice form click the Create Invoices icon.
At the top of the form, click the Customize drop-down arrow and select Customize Design and Layout.
Note: If you don't see the Customize drop-down arrow, you may need to resize or maximize the window.
Click the Customize Data Layout button.
At the bottom of the Additional Customization window, click the Basic Customization button.