Dear Felix
Allow me the pleasure of inviting you to the grand opening of [GRAD OPENING, ex. our new Tempe office]. [DESCRIBE SUBJECT OF GRAND OPENING, ex. These new premises will be the offices from which we will serve you in the future.]
[OUTLINE PROGRAM, Refreshments will be served at 2:00 PM, following a short speech from our new CEO, John Williams.] The event will be held at [LOCATION, ex. 12453 Second Street, on the north-west corner of Second and Third].
[MENTION REQUESTED NATURE OF RESPONSE, ex. Please tell me whether you are able to come by calling me at XXX-XX-XX.] I hope to see you there.
Regards
Lydia