The proper way to write a wedding anniversary invitation depends on the style of wedding and the message the sender wants to convey. Formal wedding anniversary invitations tend to be less emotional and more matter of fact, while casual wedding anniversary invitations are more emotional and tend to express personality of the couple more.
LCI Paper gives various examples of casual wedding anniversary invitations that showcase the creative preferences of the couple celebrating an anniversary. Many of these invitations are written in poetic verse, while others may feature a portion of religious text, song lyrics or a meaningful quote that the couple wishes to identify with their relationship. These invitations generally feature a creative introduction from the couple followed by the details about the event, such as time, date, location and attire.
Formal wedding invitations tend to stick to the basics, starting with a formal invitation for the guest to attend the event and followed by the relevant logistical details. Most formal wedding invitations end with the names of the couple, but LCI Paper notes that the names may also appear at the beginning. Golden and silver anniversary invitations tend to follow the formal style, but many are casual as well.