If you're completely new to tabletop RPGs, you can't go far wrong with Index Card RPG or The One Ring Starter Set. Both are superb introductions to the hobby and are easy to get your head around, so greenhorns can be rolling dice in no time.
The D&D starter set or Essentials Kit are also brilliant places to begin. They explain the rules in an easy-to-understand manner while also providing a pre-written adventure to play through.