Inner envelopes wedding invitations are typically more traditional and formal in their design since they include double envelopes.
The inner envelope holds the invitation along with any enclosures and is sized to be inserted into the outer mailing envelope. You will also notice this inside envelope is not gummed and remains unsealed.
You may choose a colored lining for the inner envelope that coordinates with your invitation design. This is optional since an extra charge is involved.
Inner envelopes wedding invitations have two envelopes that need to be hand addressed. The inside envelope will contain only the names of invited guests from each household and the outside mailing envelope will contain the formal mailing address.