It's best to avoid abbreviations and punctuation. Spell each word in full, including names of places, cities, states and addresses. The exception to this is St.(Saint) and Mt.(Mount) for the addresses and Mr., Miss and Ms. for the outer envelope.
The date should be spelled out, Sunday the sixth of August. The year may be spelled out or written numerically for a less formal invitation.
Write names in full, including middle name. It is preferable to omit a middle name rather than use an initial.
Use roman numerals in names instead of the second or 2nd.
If the ceremony is in church use request the honour of your presence. Ceremonies in a non-religous area should use request the pleasure of your company.
The opening of the invitation needs to reflect who is hosting the wedding. Mr. and Mrs. John Smith request the honour of your presence at the marriage of their daughter Sabrina Christine to John Christopher Jones.
should be addressed to the recipients by first name.