Many records in one database table or several tables?

Question

MySQL

We make a widget for websites. It is necessary to store information about all visitors of all connected sites. In the future, there will be millions of records.
MySQL DB.
Which of the options is better in terms of performance:
1. Store everything in one table
2. Make a separate table for each site
?
Perhaps there are links where you can read more about this. Thanks in advance for your advice.

Answer 1

1. Store everything in one table
Proof

Answer 2

In the future, there will be billions of records :)
If you use cookies and some ID for authorization, then the worst case for you is when the user does not support cookies at all, thus. each request is a unique user.