Also, order extra envelopes for mistakes. Invitations and announcements should be handwritten in black or blue ink. Both envelopes should be in the same handwriting. You may want to consider calligraphy. It creates a very elegant look for your invitations.
Computerized calligraphy is also available through some invitation stores.
Children's names should be listed on the inside envelope on the second line. Never use and Family on the envelope. The rule is, if children are not listed on the envelope, they are not invited. Any children over the age of 18 receive their own invitation.