him his in english

Similarity

'His' and 'him' are both third-person pronouns. It means they are used to refer to a male person already mentioned or easily recognizable.

'Him'

'Him' is an object pronoun which means it is used as an object in a sentence. Look at the following examples:

I love how the smallest things make him laugh out loud. 

 Here, 'him' is the direct object of the sentence.

You can not share that secret with him. 

 Here, 'him' is the object of preposition.

It's him on the phone again. You have to talk to him eventually. 

 Here, 'him' is the predicative that comes after the verb 'be'.

'His'

'His' is the possessive pronoun or the possessive determiner of the subject pronoun 'he'. 'His' shows someone's possession or ownership of something.
If it is followed by another noun, it is a determiner. On the other hand, if it appears without another noun, it is a pronoun.

He took his dog out for a walk. 

 'His' is followed by the noun 'dog' and shows that the dog is possessed by a male person.

My car was red. His was light blue. 

 'His' is a pronoun replacing the possessive phrase 'his car'. 

Source : https://langeek.co/en/grammar/course/182/his-vs-him