How to print full page without cut off?

It sounds like you solved it another way, but for future reference…

Photoshop has no direct control over any printer; it always works through the software that comes with the printer. Therefore, it uses whatever margin values are handed to it by the printer driver software. Different printers have different margins. For many printers, the default margins do not go edge to edge, but it is often possible to get smaller margins or borderless printing by changing settings in the printer driver software, not in Photoshop. After you change options correctly in the printer’s own settings, Photoshop picked those up.

In the example below, the printer defaults to certain margins when the US Letter paper size is selected. But if I click Print Settings to get to the macOS and printer driver software options, and change the paper size to Letter (Print Area-Large), that tells Photoshop that the margins have now been minimized. There is still a small margin at the top, because many desktop printers need a little bit of area for reliable paper transport. The exact default margins differ depending on the printer, and not all printers can print edge to edge.

i used the Professional Print & Layout software and was able to do it. i was able to drag the corners over the edge. 

Hi @Krystal26767443fxpm go to Print Settings and change your printer options to allow edge to edge (borderless) printing.