If it specifies an alphabetic cipher, then the original map used letters only:
ABCDEFGHIJKLMNOPQRSTUVWXYZ. If it specifies an alphanumeric cipher, then the original map usedletters and numbers: ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789

Encrypt the message “SEND SUPPLIES” using an alphabetic Caesar cipher with shift 7 (mapping A to H).