Change Font Color, Size, and Style
Applies to: 
SQL Server
Azure SQL Database
Azure SQL Managed Instance
Azure Synapse Analytics
Analytics Platform System (PDW)
You can customize the way the text appears in the Editor as well as other places in SQL Server Management Studio.
To change font color, size, and style in the Editor
Click Options on the Tools menu. Click Environment, and then click Fonts and Colors.
In the Show settings for list, select Text Editor.
Change the font, size, display item, foreground and background colors.
Note
Click Use Defaults to return to the default settings.
There is only one font setting for the Editor and it affects all editors in SQL Server Management Studio. You can change the color based on the text type (such as comments and statements). Monospace fonts appear in bold in the Font list, and you can apply bold settings on a per-text-type basis. For example, you can format comments and operators bold, and the other text types are unaffected.
The settings for text color and font type are global for all text element types, such as comments, strings, and so on.