gpa on ucas

please tell me how the system works. i do not get it.
is it mandatory for a US student applying to UCAS to mention his/her school grades?
Mine are pretty poor, though I have good AP scores.
Can I not put the GPA and school grades in? Is it mandatory?
Please explain I’m really frustrated

What is not clear about what is asked for in the UCAS form?

It relies more on test results, but it depends on what country you are applying from. You can include your GPA, but it is not given the same weight as the tests. I suggest you go to the Student Room, a UK site. Also, look at advice in other threads, there are plenty. One very knowledgeable person to look out for is collegemom.

@alcibiade how do you know how it is for the “Korean High School Diploma”? I can’t really try it out cuz I’m not applying right now

We want to be helpful on this site, but you need to do the basics yourself. It appears you are asking others to do the work that you need to do. The requirements are clear and there for the finding, you have to read it and the best place to start is the Student Room. When my daughter decided to apply to Cam, she got a book about how to do it and read when she was 12 years old.

Last autumn you had a bunch of threads on applying to Oxford, LSE and Princeton (the last presumably being your first choice, given your user name), including on GPA for UCAS.

Now you are asking about it again, but saying “I can’t really try it out cuz I’m not applying right now”. If you are not applying,why does it matter?

Also, I don’t understand whether you are applying from the US or Korea.