how to configure a message of the day banner in packet tracer
R1>
R1>en
R1#config t
// 'banner motd' is the preserved words for setting day banner
// '#' is for declaring exit character. This could be anything. It indicates end of message
R1(config)#banner motd #
Enter TEXT message. End with the character '#'.
WARNING: Unauthorized Access is Prohibited.
#
R1(config)#exit