Engagement parties are usually the first time family and close friends of the couple are able to formally meet and greet each other. Although engagement parties are meant to celebrate the couple's engagement, they are also a way to introduce the couple's families to each other. As with wedding invitations, engagement party invitations should be sent out well in advance.

Traditionally, the bride's family hosts the engagement party, but often the couple hosts it themselves, and it is entirely acceptable for the groom's family to host it. Invitations should be sent out two to four weeks before the party, according to Emily Post. There isn't an etiquette rule in place for the actual invitations, as they should reflect the style of the event. If the party is formal, the invitations should be formal. If it is a casual affair, the invitations should be casual. Everyone who is invited to the engagement party should also be invited to the wedding.

When it comes to weddings, invitations should be hand-addressed in ink, and preferably in calligraphy. Engagement party invitations, on the other hand, are usually more casual. The most important thing is to keep it simple and clear. Write out all street names and, in most cases, write out full titles and first and last names. There is one exception. Because there is no inner envelope, you may want to write, for example, "The Hamilton Family" rather than "Doctor and Mrs. Thomas Hamilton" if children are invited.