Wedding Invitations

I believe you do it according to size, go from larger to smaller facing the rear of the envelope

When two envelopes are used, the invitation (folded edge first for a folded invitation, left edge for a single card) and all enclosures are put in the inner envelope, facing the back. If no inner envelop then the front of the inviation should face the back of the envelope.

The inner envelope is placed, unsealed, in the outer envelope, with the flap away from the person inserting it.

All insertions are placed in front of the invitation, so that they face the flap (and the person inserting them). In the case of a folded invitation, the insertions are placed in the same direction but inside the invitation instead of in front of it.