If the POS screen is too large for your display on Rent It Biz App, press the Ctrl key and the + or - button at the same time. Then press Control + F5 then exit. Start new ticket to preview. You nay have to repeat this process for desired screen size.
If using Google Chrome, click on the menu (3 dots, "...") underneath close browser screen button in upper right hand corner. Click the "-" button to make the screen smaller. Click the "+" button to make the screen larger.