The name for the printer entry must be a valid SAS name: it must begin with a letter or underscore (_), and subsequent characters can be letters, numbers, or underscores. You are not allowed to use the name of another entry in the printer list.
There are no restrictions on the description.
Note that after you have entered the printer commands for a certain name and description, you can no longer change the name and description in the Add a New Printer window. However, you can use the R (Rename) line command on the Printer List window to change the name or description.