TMs are single-use items that teach a Pokémon a specific move. They are found throughout the region, given by NPCs, or purchased from Poké Marts. HMs, on the other hand, can be used infinitely and teach moves essential for navigating the world, such as Cut, Fly, Surf, and Strength. HMs are often required to progress the story, so make sure you have a Pokémon that can learn them.
