Some States and counties make it illegal to live off the grid while other states and counties allow off the grid living.
You would have to check with your local laws where you plan to live off the grid to be sure.
Living off the grid in most towns and cities would get you fined or a lien put on your property while rural places would likely not bat an eye if you were living off grid.
Living off grid means not being hooked onto electricity, city water, natural gas, telephone, internet etc.
Although some people live partially off grid but have internet access which is okay since some people make their money through Youtube videos and online websites when living off the grid.
But they should say they're living partially off the grid because a person actually living fully off the grid wouldn't even have a phone or internet access which is hard to do today.