Hi Carlos,
I'm new with SQL Server databases, could you explain me please how the initial size works?
I suggest you to kindly follow SAP doc at Changing the Size of the Database Files - SAP/ MS SQL Server DBA in CCMS - SAP Library
& SAP Note 363018 - File management for SQL Server
I would like to assign 20GB more to increase the space in those database files
You could increase the initial size by following as like
In Database Properties, select the Files page.
To increase the size of an existing file, increase the value in the Initial Size (MB) column for the file. You must increase the size of the database by at least 1 megabyte.
To increase the size of the database by adding a new file, click Add and then enter the values for the new file.
Hope this will help you.
Good luck !!