***** NOT A TEACHER *****
Good morning, Mohamed.
(1) These two words are really difficult and confusing.
(2) If you get time, type each word in the "search" box at this website. You should find some good posts.
(3) Also check the Internet. Type in "prepositions onto/into."
(4) Very briefly, I can report what Michael Swan's popular PRACTICAL ENGLISH USAGE says: (I have changed his examples a little bit)
The lady walked IN the garden for 15 minutes. Then she walked INTO her house.
There was a cat ON the roof of the house. Everybody asked, "How did the cat get ONTO the roof?"
Have a nice day!
Student or Learner