Llamas are one of the animals you can befriend and ride in Minecraft. The cool thing about them is that they can transport large amount of items if you lead them, making them good if you want to change your main housing or something like that.
Llamas can spawn in savanna biomes or mountain biomes, and they mostly spawn in herds up to six animals. Before you can ride one you will need to tame it, which can be done by feeding it with either 10 wheat or 5 hay bales.
Once the llama is tamed, take of all your equipment and try to mount it. It might still kick you off a few times, but just keep trying, and it will eventually let you stay there and ride it.