how many databases does wordpress need?

I don’t understand your question. You can have multiple WP sites sharing the same database if you set a different table prefix (in wp-config.php) for each, but the most secure method is to give each site it’s own database (with its own credentials).

What are you trying to accomplish?

Dear Steven Stern

I’ll explain a little. I have a claim from a client.
But the judge thinks that the website I installed had two databases.
Of course I understand that by default wopress only handles 1 single database. but I need a confirmation from an official source so that they believe in my word.
Does a normal WordPress installation need 1 database?

1 site = 1 database

I really apologize for asking these things here and wasting your valuable time. but I need this clarification.

Yes. Normally, it’s a database per site using MySQL.

thank you very much for your help.