Specify the prefix and the table name like this CREATE TABLE $ table_name.
dbDelta ($ sql); is a function that checks if it is a WordPress rule when creating a table. You should pass this function when creating a table.
Also, dbDelta () is in wp-admin/includes/upgrade.php. It is not usable by default, so it needs to be included.
You have now created a table in the database.
This article title
How to create a database table from a WordPress plugin