How do you address wedding invitations to a married couple with different surnames?

For a married couple with different surnames, the simplest and most respectful approach is to give each person their own line on the envelope. For example, write "Ms Anna Brown" on the first line and "Mr Tom Green" on the second line. If you know one person better, put their name first, but it is fine to go alphabetically or by whichever feels natural. If they have titles such as Doctor or Professor, include those. If they share a house, you do not need to write "and" between the names, as that is more common for couples with the same surname. If one partner has changed their name and the other has not, use the names they actually use, not what you assume. If you are unsure, ask them directly or check their social media. For a more formal invitation, you might write "Mr Tom Green and Ms Anna Brown" on one line, but two lines are clearer. The same rule applies if they are married but one kept their maiden name or a previous married name.