Save-the-date cards are informal announcements sent to guests to inform them of an upcoming event, typically a wedding or significant celebration. These cards are usually sent out several months in advance, allowing recipients to mark their calendars and make necessary arrangements to attend. The design of save-the-date cards can vary widely, often reflecting the theme or style of the event. They usually include essential details such as the date, location, and names of the hosts. While not a formal invitation, they serve as a helpful reminder for guests to reserve the date.