Before you run any electrical wiring outside whatsoever, you absolutely need to make sure you call utility location. Essentially there’s two ways to run wire into the ground. You can do direct burial cable, which has to be dug down to 24 inches deep. You need to have a trench 24 inches deep before you even touch the electrical cable for it to be valid, up to code, and safe.
You can put it into a conduit body (PVC or plastic conduit body) and at that point by code and by law you need to have a trench that is 18 inches deep before you even touch the top part of the conduit. There is also a metallic conduit that is called rigid conduit, which actually only has to be dug down 6 inches deep. But it is no fun to work with whatsoever.
Those are the main ways that you can put them in. If you do decide to proceed with any of these methods, you want to make sure that your depth is proper, that you know your distance, that you know if you’re going too far whether or not it will be enough power once it reaches that point.
It is very important to contact a licensed and certified electrician to come out and do this work for you, because it becomes extremely hazardous.