This selection won’t affect existing text. You can set a default font and font size for future text added to your PDF.
HOW TO REDUCE PAGE SIZE IN ACROBAT HOW TO
How to Set a Default Font and Font Size for Adding Text in a PDF Your format changes should appear immediately.
HOW TO REDUCE PAGE SIZE IN ACROBAT PRO
Pro Tip: If you want to select the entire text box, place your cursor in the text box, and then select Ctrl + A on your keyboard. You can have multiple formats within the same text box. Your text box should be deleted immediately. Alternatively, you can right-click and select Delete from the shortcut menu.
Resizing cursor (Enlarged to show detail)