New employees are given free training in the repair of mobile devices.
Employer Verified Available to US-based employees (Change location)
They give you a couple of outdated devices to tear down and put it back together, then shove you into working on customer devices. That was when I started, though. I graded higher because they have a more comprehensive training program that prepares you for the job.
The training is adequate but don't rely on it. You should be able to learn on the job how to do many repairs that you won't get to do during the training.
The job training is great, they teach you everything you need to know for the job.