The Page Orientation controls the way a page is oriented for normal viewing.
Note: Changing the orientation won't impact/update any previously created forms.
Steps:
Navigate to the folder where the template was originally created (e.g either in the Home Folder/Team Folder)
Click on the Template Library tab
Note: If the template was created in a Team Folder, click the Templates tab
Select the template checkbox
Click Edit Template
Select the Settings tab
Scroll down to the Page Orientation section & use the dropdown to toggle between Landscape & Portrait
Click Save