PowerPoint: Exporting to borderless PDF on macOS

1. In the menu, click on File → Page Setup…; a dialogue should open.
2. In the Size section of the dialogue, take note of the Width and Height settings.
3. Click on Options.
4. In the Format For dropdown menu, select Any Printer
5. If the dimensions below the Paper Size dropdown menu correspond to the Width and Height you took note of in step 2, skip ahead to step 10.
6. If not, click on the Paper Size dropdown menu and select Manage Custom Sizes….
7. Create a new custom size with the + button. Set a Paper Size corresponding to the Width and Height you took note of in step 2, and a Non-Printable Area of 0 on all 4 sides. WARNING: Modifying the non-printable area sometimes resets the paper size; so double-check the paper size, then confirm with OK.
8. Make sure your newly created custom Paper Size is selected, then confirm with OK.
9. … and confirm with OK one last time, closing the outermost dialogue.
10. Open the print dialogue (e.g. with Cmd+P).
11. If you see a Show Details button, click on it.
12. Make sure that Scale to fit paper is unchecked.
13. In the lower left corner, there’s a dropdown menu (it should say PDF). Click on it and select Save as PDF.
14. Confirm the save. The PDF should be borderless :) Whew!