I’ve been thinking of some ways to personise the wedding invitation. These round stamps can be used to stamp the envelopes on the back:

Some of the websites I have been to make you design your own stamp which can take ages. I would prefer if they already had samples like this one that you could just slightly modify:

You can then use your stamps to personalise gift wrap. What a neat idea - although we have to be careful not to smudge the seal after its made.

If you really wanted to …