Minecraft 1.16 updated added emotes. Mojang decided that emotes are a common feature in many games and to join the bandwagon. Although they're not a major feature in most games, they can greatly improve a game's quality-of-life.
Although there are not many emotes in Minecraft at the moment, there are enough to give you more than just a few. These emotes can be used in Java Edition.
Java Edition has many key differences to Bedrock Edition. Java Edition emotes can be obtained through mods or client server.
If they have not customized the controls, players can click “B” on a computer to play Java Edition games. It's the left button of the D-pad for console gamers. The emote wheel will appear if this is done in a world.
Java Edition gamers will then be able to use their mouse to choose the emote that they wish to use, and click it. They will then begin to use the emote of their choice in-game. You can repeat the process to do the emote or choose another.
Before emotes can be used in-game, they must be created in the character creator menu. This is done before you load up a new world. There are slots in Minecraft that can be used as presets to create skins.
Each skin can have a different loadout of emotes, but they must be set up first. It will then be saved, and the skin will continue to be able use the emotes.