How connect to my database from php?

Question

i want to do a web,and a login,but i have this question

Answer 1

https://www.w3schools.com/php/php_mysql_connect.asp

Answer 2

Rhyr Core,
Additional to Rhyr Core's answers.
Make sure you write it in PDO,
It is more secure and should prevent SQL injections when written correctly with prepared statements.

Answer 3

thanks,i want to create a web with login and databases,html