SharePoint needs to create some databases in your database server.
those databases include logging database, administration database, property database, crawl and search databases, content database, profile database and more. you can find more details here.
during the initial configuration you might encounter the following error:
this is due the fact that administrator user does not have create privileges on the “master” database in order to create the described databases.
add “dbcreator” security role to the SharePoint admin user:
1. Run Microsoft SQL server management studio
2. Go to Security –> Logins –> <Admin User> –> Server Roles
3. Check “dbcreator” role for the user
4. Re-start SharePoint products configuration wizard.