Mai is simply I Mujhe is mai + ko so it literally means "to me" and often it is used when you want to say to me of course haha in urdu there are also some grammar constructions in which mujhe is used there are actually a lot of these but two common examples are when talking about things we like for example mujhe pasand hai (to me ...is liked) mujhe machli pasand hai means to me fish is liked. And the second way is when talking about things we need/want mujhe pani chahiye (to me water is needed)

mujhey in urdu...as we use..."I" in I like or I love...."main" is myself in english...

No perfect rule. You have to learn their usage. I am Pakistani. میں پاکستانی ہوں۔ I play football. میں فٹ بال کھلتا ہوں۔ I like you. میں تمہیں پسند کرتا ہوں۔ مجھے تم پسند ہو۔ مجھ کو تم پسند ہو۔ To learn more about Urdu language, contact me.

"main" is subject case only, "mujhe" is for object cases, and it comes in three versions for different levels of language (style): "mujhe" (literary and educated), "mujh ko" (everyday usage), and "mere ko" (substandard, but also widely used)

mujhey in urdu...as we use..."I" in I like or I love...."main" is myself in english...