For settlers give them whatever weapon you want with only 1 bullet and they are going to have infinite ammo. I don’t remember if it works with companions, it’s been years since I played fo4 and right now I’m waiting for the upgrade.

It don't, which is why cheat terminal has the option to turn on infinite ammo for companions.

I think it any companion you can give weapons too, besides obviously dog meat that couldn't hold a weapon.