Hello! Can you tell me what kind of knowledge you need to have to get a job as a junior? And in general, what types of work are related to electronics

 

Completing this would be a good start.
http://www.compatt.com/Tutorials/NEETS/NEETS.html

 

You will need a background in general electronics -the NEETS manual naspook showed you in post #1 is a great example. On top of that you will need specialized knowledge for the area in electronics in which you are to work.

Just a guess, but it is probably way too early for you to pick a direction, and besides, becoming proficient in the basics will take you a year or two. That should give you some time to think about where you want to go with your new found knowledge.