Okay kiddo, have you ever heard of an apprentice before? It's when someone who is just starting to learn a skill or trade works with someone who already knows how to do it. Sort of like how you learn from your teacher at school.
Well, sometimes apprentices want to travel and work in different places to learn new things from different people. This is called "apprentice mobility." It means apprentices can go to different cities or even countries to work with different folks and learn new skills.
This can be a really great way to learn and grow as an apprentice. But sometimes it can also be hard to travel and find new places to work. That's why there are programs and organizations that help apprentices with mobility, so they can keep learning and exploring no matter where they go. Pretty neat, huh?