Why an invitation? We celebrate Shabbat every Friday! "Everyone" just knows about the Festivals, we don't need to send out an invitation. Let's just invite them the next time we see them (perhaps the day before in the grocery store).
An invitation is not meant to be an inconvenience for you the sender, but rather a friendly gesture to the recipient. In the world we live in today, life is very busy. It is one of the kindest gestures to send an invitation to a potential guest. They can check their calendar and see if they have a previous engagement scheduled...such as celebrating with someone else for a Shabbat or Festival. A good rule of thumb is to send out a dinner party invitation at least four weeks in advance.
For women who prepare and host Shabbat meals often, an invitation allows excitement for them to await an evening off! An invitation sent ahead of time will allow the family to adjust their grocery budget so as not to purchase so much food that it would spoil. Can you think of other reasons why sending an invitation is a practical and kind gesture?
Include R.S.V.P. information on a written or printed invitation and just type "R.S.V.P." in the lower left hand corner of an emailed invitation. On the lower right hand side of the invitation you will need to let your guests know how to dress by saying, "Black-Tie" or "Casual." Though it is not common practice for Shabbat or other Jewish Festivals, if the hostess so decides to have a themed dinner where the guests should dress accordingly, this needs to be on the invitation in the lower right hand corner.