SQL server installation create some system databases automatically, you can see these database in your SQL server management studio:
| Database | Description | Database file name | Log file name |
|---|---|---|---|
| master | Contains all system level information for a SQL Server system. It records information about all login accounts and all system configuration settings. | Master.mdf | Mastlog.ldf |
| model | The template for all databases that are created on the instance of SQL Server. | model.mdf | Modellog.ldf |
| msdb | This database used by the SQL Server Agent for configuring alerts and scheduled jobs etc | Msdbdata.mdf | Msdblog.ldf |
| tempdb | Contains all temporary tables, temporary stored procedures, and any other temporary storage.tempdb database is re-created every time SQL Server is started so the system starts with a clean copy of the database. | Tempdb.mdf | Templog.ldf |