I got monster hunter for the 3ra and I wanted to ask
what I the best weapon for beginners?

For what console?

Lance is pretty good. High defense, the damage can still cut tails, and counter attacks feel gooooood.

Sword and Shield is very simple (and is in fact the starting weapon for the large majority of the games), as is Great Sword and Hammer. Longsword is relatively simple, but a little more complex than SnS and GS. It goes up in complexity from there, really.

Each weapon has a specific "feel" to it, however. You may find using the Charge Blade or Hunting Horn easier than using the Longsword or Dual Blades. It's really just as simple as trying them all out. Don't get discouraged if you fail a few times, that's just Monster Hunter being MH. Most games give you one of each in your weapon box, give them all a try.