Is this correct pronoun they has many books?

No, that sentence is not grammatically correct. Here's why:

* Pronoun Agreement: The pronoun "they" is plural, while the verb "has" is singular. They need to match in number.

Here are a few ways to correct the sentence:

* Singular Subject: "They" is plural, so you need a singular subject to use "has": "Someone has many books."

* Plural Verb: If you want to keep "they," you need a plural verb: "They have many books."

Let me know if you have any other sentences you'd like to check!