Would you please help me to modify my sentences. Sure!

I is usually used with am  -   “I" 这个字母通常会和 ”am" 一起用。

You are still learning, so you will need to add "ing" to your verb - 你现在正在学习玩高尔夫球，所以你必须要在动词上加上 "ing"

In English, there is a difference between learning and studying, studying is used for topics to do with academics or books, like the economy or history, while learning can be used for more things, including non-academic topics like golf. - 在中文里“学习”和英文有些不同。Study 是使用在和书有关的题目，比如经济上的学习，或者历史上的学习。"I am studying economics," "I am studying History." Learning 会在这个句子比较适合，因为 Learning 本身可以用在更多地方，包括和书没关的题目，比如说高尔夫球。

I want to learn English.

Nothing wrong with this sentence - 这句话没错。

You can Can you help me? 

You can help me talks more of ability, where you're asking if the person has the ability to help you. - You can help me? 是在问关于能力的问题。你是在问　”你有能力帮我是吧？”, Can you help me 是 “你能帮我吗？”也就是说 “你愿意帮我吗？”

Golf is very interesting, so I love golf.

This sentence is basically correct, but you need to put a space in front of every punctuation mark. - 这句子基本上没错，可是你要记得在每一个标点符号后放个空格哦！

I need a teacher with the golf. to teach me golf

I need a teacher - 我需要一位老师

to teach me golf - 来教我玩高尔夫球

Would you please help me to modify my sentences.

(I practise golf.) (I plan to play golf.)
I want to learn English. (Correct)

You can help me?

(Can you help me?)
Golf is very interesting,so I love golf.

(Golf is very interesting, and I love it.)
I need a teacher with the golf.

(I need a golf coach.)

Hope this helps.

Cheers, Lance