In spoken English, the verb GET sometimes replaces the verb BE in passive sentences. We call this the “get-passive”.

And we can also use GET with adjectives to show changes over time (to become something). 

To have a better idea of what these concepts are, take a look at these explanations and exercises:

https://www.grammar-quizzes.com/passive2.html

https://www.esl-lounge.com/student/grammar/3g3-get-passive.php

http://english-zone.com/grammar/get1.html

https://www.ecenglish.com/learnenglish/lessons/get-become