The wedding invitations I am ordering say that they come with standard matching envelopes?

Question

What exactly does that mean. And is it really necessary to put the invitation in one envelope and then into another? I dont really understand all of the different pieces.

Answer 1

it just means that they have an envelope that matches the invitations. you can put them into another evelope to send but you dont need to.  

Answer 2

It comes with an envelope to mail it in. Typically, there are 2 envelopes, with one inside the other. The outside envelope is where you put "Mr. & Mrs. John Smith" and the inside envelope is where you put "John, Jane, and baby Joe". Having 2 envelopes like this is technically the formal way to do it, and it makes it easier when inviting families, or "Jim and guest", because it's hard to portray that on an outer envelope. How will you address it, "Mr. Jim Jones & Guest"?  or "Mr. & Mrs. John Smith and kids"? How will they know who all is invited? It's kinda hard to do that way.

By no means do you have to have both envelopes, just letting you know what they are for and why they make it easier. :)