Draw straight lines or align things with the ruler in PowerPoint

You can use the Ruler on the Draw tab of the Ribbon to draw straight lines or to align a set of objects. The Ruler pivots to any position you want: horizontal, vertical, or any angle in between. It has a degrees setting so that you can set it at a precise angle, if necessary.

https://support.microsoft.com/en-us/office/draw-straight-lines-or-align-things-with-the-ruler-in-powerpoint-6222c9b4-2fdf-48f7-a3fd-1687fbe2bf84