Most traditions seem to have faded and changed over the years except for an invitation to a formal event. Etiquette still exists when inviting guests to your wedding. The outer envelope is addressed to the guest and/or couple. The inner envelope indicates exactly who is invited to the event. It is a way to personalize your request to have them present at your celebration.
The inner envelope is also a way to add some unique design elements to your invitation suite. Custom liners can be made and lined inside the envelope reflecting the theme of your wedding. Options include monograms, patterns, and even just simple pearlized liners add thickness and elegance to the plain envelope.
When addressing the inner envelope, you can be formal or even slightly casual depending on the formality of the wedding. Black tie or formal weddings would require tiles (i.e.) Mr. and Mrs. Smith. A backyard or barn wedding might lend itself to something less formal where names can be used (I.e.) Jennifer and Brandon. When titles are not used, the ladies name should be listed first. If addressing to a same sex couple the one you know better personally would be listed first.
Inner Envelope Guide:
Mr. and Mrs. Smith
Married Couple inviting Children/Family
Mr. and Mrs. Smith
Jacob, Andrew, Sarah (list children oldest to youngest)
Married Doctor and Spouse
Dr. and Mrs. Jacobson
Both Spouses are Doctors
The Doctors Jones or Dr. Jones and Dr. Richardson (if spouse has different last name)
Single Invite with Guest
Ms. Jones and guest
Couples Living Together, Not Married
Ms. Thompson and Mr. Byer
Same Sex Couples
Ms. Reynolds and Ms. Griffin
This process does require one more step, but it’s worth it in the end. The invitation is the first impression and reflection of your wedding. Make sure it matches your vision for the day!