Hi Joye! Your first note is good, but there are a few minor errors. If you write using the Latin alphabet, you have to leave a space after dots and commas.

Hi everyone! My name is Joye. It's my first time I have written here.* I come from China, I study in a university, and I hope that we can be friends and I can learn from you.

* As for beginners, it's a bit complicated. You can write "It's my first note here." or "This is my first note here."

The English verbs are quite impersonal, you have to put the subject (a personal noun, a name etc.) in the sentences every time.

Good luck!

Introduce myself

hey everyone.I'm Joye.It's my first time to write here.I come from China,study in a university.hope to be friends with all of you and learn from eachother.

Hi everyone.  My name is Joye.  This is my first composition*.  I come from China, study in a univeristy and hope to be friends with you and learn from you.

Note: In English sentences if you use more than one verb, you want to use each verb in the same place.

Structure:

I + verb 1 + noun 1, verb 2 + noun2, and verb 3 + noun3.

For example:

I WATCHED television, ATE dinner, and TOOK a nap.

*composition = a piece of writing 一种文章