In most schools, teachers give students grades (which are sometimes also called "marks"). The traditional grading systems in the United States are letter grades from "A" to "F", or number grades from 0 to 100.
When you talk about a student's grades, you may use the word "get". For example, you can ask a student about the results of a test:
What did you get?
That means "What grade did the teacher give you on the test?"
The student might answer:
I got a B.
In general, English speakers talk about "getting good grades" or "getting bad grades":
I got pretty good grades in high school, but in college I partied too much and my grades started to suffer.