‘Have’ and ‘has’ are both used to denote possession, form the perfect tense, and the past tense of both is ‘had’, but they are used differently.

‘Have’ is used with

• the following pronouns: I, you, we, they. Examples : ‘I have a pencil.’ ‘We have a big house.’
• pluralised nouns: Example : ‘ Doctors have a rough time, dealing with illnesses all the time.’

‘Has’ is used with the third person singular ( he, she, it) . Examples : ‘ She has your money.’ ‘Amit has the book.’