One of the first things you'll have to do is make a guest list and when you have location(s), time and date set, you can make your invitations. These are things to consider:
2. Scroll or normal envelope?
You can also just use an ordinary piece of paper and an envelope, and with a wax seal - see prior entry - it can look just as great.
There are plenty of websites where you can find a fitting font for the text. I always use Dafont.com and they even have an explanation if you don't know how to add a new font to your writing program. Some examples could be these:
When it comes to decorations you have very free reins. It can be an illustrations of a castle or flowers in dusty colours and gold and maybe a French lily. There can be a picture of a knight and his maiden or you can just let the first letter of the text be a big beautiful and detailed picture in itself.