Question

use of has have and had difference

Answer 1

had for past
have for present
has for future and many a time with past and present too

Answer 2

has is for singular present perfect and present perfect continuous
have for plural present perfect and present perfect continuous
had is used for both singular and plural past perfect and past perfect continuous

Has and have is also used as possession
like I have my breakfast
I have two pens.

Hope it satisfies you.