Traditionally speaking, there are two types (styles) of wedding invitations: a single fold invitation and a double fold invitation. Nontraditionally speaking, there are also single cards with no folds.
Single Fold Invitation
The single fold wedding invitation is probably the most common. It resembles a greeting card with a single fold on the left hand side. The invitation itself is printed or engraved on the front and the inside is left blank. The single fold invitation is mailed in an envelope only slightly larger than the invitation itself.
Double Fold Invitation
The double fold wedding invitation is probably the most formal of invitations. It consists of a single fold invitation that is folded in half again, from top to bottom and mailed in an envelope roughly half the size of the invitation.
The Single Card
An alternative to the single and double fold invitations is the single card invitation. This is basically a single card, equal in size to the front page of the single fold invitation, with the invitation either engraved or printed on the front of the card. This option allows for greater creativity in terms of paper design and printing styles. For this reason, it is more often considered by brides planning semi-formal or informal weddings.
