InDesign CC is the best page layout program on the planet. And it would probably be the best for wedding invitations.
But, it's a professional level program, and you'd have to take some time to learn the program to achieve what you want. If you're willing to do the work, then get this inexpensive book which would answer your questions. If not, better to hire someone to create a wedding invitation:
Since they are mostly text, InDesign would be a good choice. What questions do you have?