"I haven't tell him" - yes, this is wrong. Please take some time to learn basic grammar. "I haven't told him" is correct. It means that even now, he doesn't know the news from you.

Can I say What could I did

''I haven't told him'' this one is correct another is wrong in grammar book, it is called " present perfect " the form of it is : Subject+have/has+ Verb past participle

"I have not told them" is the correct one. It is in the present perfect tense . It means I did not tell them about that thing before till now.