An "invitation" is a request for someone to attend an event or gathering. It can be formal or informal and is often sent in the form of a card, email, or verbal message. Invitations typically include details such as the date, time, location, and purpose of the event, whether it's a birthday party, wedding, or business meeting. Invitations serve to inform guests about the event and encourage their participation. They can also set the tone for the occasion, reflecting its style and significance. Common types of invitations include wedding invitations, birthday invitations, and business event invitations.