If you need more backfield space for stack or pistol alignments, or if you want less backfield to allow more downfield space for deep routes, you can move the line of scrimmage up or down in relation to the overall diagram:
1
Tap a play to open it, then tap the field icon in the toolbar
2
Tap to select the backfield space option - less, standard or more - that works best for your play diagram
3
Tap the green checkmark in the upper right corner