Is it necessary to get married when traveling with a group in Europe?

Going to Europe with a group also needs some information such as real estate license.

For example, if two couples go to play, if both parties have proof of assets, then there is no need to provide marriage notarization; However, if only one party has the real estate license and the other party does not, then the party without the real estate license must provide marriage notarization, so as to borrow the real estate license of the other party.