It would require a drill, a drill bit, an accessory called a tap, and a tap wrench. First you ensure that you’ve selected a drill bit sized to match the tap by consulting a drill-and-tap chart.

i need one of those charts where you slide the card back and forth until the screw size you want is in a certain window, and then the rest of the windows ...

I quickly calculate proper tap-drill diameters using this simple formula. Tap-drill diameter equals nominal diameter minus thread pitch. For example, drill size for a 3/8-16 thread is 0.375 0.0625 ...

Luckily, your 3D printer takes care of almost all these steps. By simply designing your holes to be the tap drill size you can hand tap fairly strong threads in your 3D printed parts.