Move

A move, also know as attack or technique, is the primary skill used in combat by Pokémon as well as the core of the battles along with moving.

As it is an action RPG, moves in Pokémon Generations are sensibly different from what it's been seen in the handheld game to this point.

The base of Pokémon Generations is that you can perform a move as long as you have enough stamina. Stamina is consumed, in addition to when you use a move, when you perform certain actions like jumping or flying. Moves can consume a fixed amount of stamina like, for example, Tackle, can consume stamina over time while being used, like Withdraw, or both, like Dig.

Pokémon can use 4 moves at a time as their moveset in a single battle. This moveset can not be modified while in combat. However, it can be modified at any time while out of combat and have any of its moves replaced by any of the other known moves of the Pokémon.

Moves can fall into three different categories: physical, special and status. Phyisical moves involves a physical contact with the opponent, either direct or through some projectile. Special moves are the ones requires no physical contact with the opponent. Status moves do not cause a direct damage to the opponent. although they can cause damage over time like Leech Seed.

Pokémon Generations will include mainly moves from Generations I and II, although it may also include moves from other Generations as well.

Learning
Pokémon can learn new moves as they level up. You can check which moves a Pokémon can learn by this method in its page.

Unlike the handheld games, you won't be able to learn moves from Technical Machines (TMs) or Hidden Machines (HMs). Instead, you will be able to learn new moves from Move Tutors instead, that will teach you a certain move to as many Pokémons as you want. HMs will not exist as such and will be treated mostly as ordinary moves, with the exception that some of them might be used when out of combat too.

As stated above, once learned a move can be added to the current moveset of the Pokémon at any time when out of combat.

Leveling Up a Move
In Pokémon Generations moves have levels themselves. As you use a move, it gains experience and eventually levels up, increasing in power.

Once mastered, that is, once it has reached its maximum level, you will get the chance to learn an improved version of the said move. For example, once Quick Attack has been mastered you will unlock Extremespeed. This is the only way to learn certain moves.

Move variance
The same move may be performed differently by different Pokémon. For example Weedle's Poison Sting is focused on poisoning his opponent while Nidorino's is more focused in dealing direct damage. It can even vary as the move levels up.

You will have to take this in count when choosing your Pokémon team, as some Pokémons will perform a certain attack in a way that suits your playstyle better than others. You can check how moves are performed by different Pokémons in the corresponding move page and also in the Pokémon's page.