I have created a database \"test\" with some tables in MS SQL Server 2008 R2 (i.e. MS SQL Server Management Studio).
Now, I need to export this database as a MDF file.>
If you mean that you want to be able to attach the database on another server, then this is what you can do:
Detach
)Databases
and click Attach
)This is the path where you will find MDF file:
C:\Program Files\Microsoft SQL Server\MSSQL10_50.MSSQLSERVER\MSSQL\DATA\