The occasion, date, time, and place should be written in an invitation.
If you have a map, include it in the invitation.
List all kinds of drink that will be served in the event.
Give a telephone number for confirming the invitation.
Refer to a kind of clothes in the invitation if necessary
Attach a stamped envelope with your invitation if you need a reply.
Say you are looking forward to seeing them.
Do not use abbreviations in an invitation.
Specify the arrival time and the dinner time.
Mention in the card if the presents are not needed.