The smallest details are so important. The envelope is the first think your guest will see from the stationary designs, make it a WOW moment.
It's many ways to design the envelope. It's easy to make it and you can do it yourself.
Find envelopes in the color theme you have choose for your big day. It might be expensive to ask the next printer shop to make the color you have chosen but there is so many places you might find very similar colors. I recommend Amazon to find beautiful envelopes.
Do you have a logo design for the wedding? It's personal and you can re-use it on all designs for the wedding and also for the future anniversary celebrations. You can find pre-made logos that are budget friendly and they are adjusted to your letters, names and date. I have a collection of logos that you can look at.
Note it's service based product.
Wax stamps are so beautiful and creative. You can find beautiful stamps with flower icon for example. You can find then in most creative shops, I recommend Søstrene Grene and Amazon. You can also have them produced with your own logo or icon.
This is another way to mark the envelopes. Use ink stamp your logo on the envelopes.