It’s a honor that you were invited. When you receive your invitation, it will have a rsvp to respond by a certain date. If you are unable to attend you should respond back with your regrets to attend, Its courtesy. If you are able to attend respond back with a yes. If you respond with a yes, please show up! There is a lot of detail, money, and time into planning a wedding. Have the respect to show up. The invitation is for you or whomever it is addressed to on invitation. For example, If the invitation is addressed to Mr. and Mrs. Brown, these are the individuals Invited. It’s courtesy to bring a gift from the couples wedding registry. It’s important to review the event dress code. Most importantly Enjoy the Wedding!