If after attempting to edit your printforms they are printing over multiple pages - mainly blank, there are two options.
Restore printforms file from Backup
This article will step you through the process - Restoring Printforms File
Resolving one of the below possible causes:
An object is overlapping two parts of the form
Parts are indicated by a broken line (............) whilst in layout mode of a form.
If any objects overlap multiple parts, this issue may be experienced.
Similar to an object overlapping a 'part' divider, two objects overlapping each other will result in a similar issue.
'Sliding' may need to be enabled
Select the object on the layout and in the top FileMaker Menu go to Format > Set Sliding/Printing…
In the popup window that appears make sure that “Sliding based on – All above” is checked and that “Also reduce the size of the enclosing part” is checked.
By turning on sliding for objects this means that when viewing the layout in Preview Mode the object will slide up the page if other objects in the layout are empty of text.