To specify that a file extension is a COBOL program or copybook: 
               
            
 
            
             
               
               - In Visual Studio IDE, click 
                  Tools > Options. 
                  
               
- Expand 
                  Text Editor and click 
                  File Extensions. 
                  
               
- In the 
                  Extension field, type the extension you want to add. There is no need to type the extension with a dot.
                  
               
- From the drop-down list box under 
                  Editor select 
                  Micro Focus COBOL and then click 
                  Add. 
                  
               
To associate extensionless files with the COBOL language: 
               
            
 
            
             
               
               - On the same page, check 
                  Map extensionless files to and select 
                  Micro Focus COBOL from the adjacent drop-down list box. 
                  
               
- Click 
                  OK.