"Have" and "has" are both forms of the verb "to have" and are used to indicate possession, ownership, or the presence of something. The main difference between "have" and "has" lies in their subject.
• "Have" is used with the pronouns "I," "you," "we," and "they." For example:"I have a book," "You have a dog," "We have a car," "They have a garden."
• "Has" is used with the pronouns "he," "she," "it," or with a singular noun. For example:"He has a cat," "She has a bike," "It has a red color," "The company has a new office."
It's important to remember that "has" is used with singular subjects, whereas "have" is used with plural subjects. Also, when forming questions or negative sentences, we usually use "have" or "has" as auxiliary verbs.
For example:
• Questions:"Do you have a pen?" "Does he have a sister?"
• Negative sentences:"I don't have a car." "She doesn't have any siblings."