I am planning on running an underground electrical cable to my garage. I plan on placing a 100 apm panel in the garage and run from my house main electrical feed. What kind of wire do I need to do the job?

You cn use what is called #2 URD cable, which will have three #2 wires for the 2 hots and 1 neutral, and a #4 for the equipment ground. This cable is also called "Trailer cable". This is aluminum wire, and the terminations need special but easy treatment. After stripping, wire brush the bare aluminum, coat with anti-oxidant compound, and torque the connections properly.