The CMS 1500 option is generally used for printing a claim form.
Generating the paper claim using this option would open the information to the PDF viewer software on your computer with text alone and without any borders or lines. The red-lined form (CMS 1500) would have to be placed on the printer tray before giving the print command to have the text printed to the corresponding boxes on the red form.
HCFA-1500 option shows the claim information along with lines and borders in the PDF viewer. On the PDF viewer, the information will appear similar to a printed paper claim form.
The option is typically used for viewing the information that would populate in a printed claim form. This option is not to be used for printing and mailing. If insurance or a party requests you to fax the claim form, you can use this option to print it on a white paper sheet and fax.