This image below is from my passport. I obtained the passport not because I was about to travel but to have a document that shows I am a British citizen, to help facilitate my marriage to my Russian national fiancée, and to be able to travel with her as we may do in the future. I have removed a number of details including my signature and made it so that only the fact the passport exists is demonstrated.
To help the supporting process there was also additional support (shown below) towards demonstrating that were together and found ourselves enjoying a strong relationship which we decided could only lead to marriage. This was a colour photocopy of a photograph of us and handwriting below it by a notary. I reproduce the supporting paper, which here has the identifying features removed and feathering of another image of us has been added in order to protect the handwriting which has itself been recoloured.
In neither case are these items displayed here for proof purposes. They are displayed for reference purposes only to those documents.