We have a great selection of invitations for those milestone birthday from ages 18 through to 90. There are two main types of invitations which is sheets and cards. Invitation sheets have the design and the invitation details both printed on the front and some of them require folding before being inserted into the envelopes. Cards on the other hand have the design on the front and the details are written on the inside. All of our invitations whether they are cards or sheets come with envelopes that are the correct size.