The tradition of inner and outer envelopes dates back to the time of white gloved butler and muddy streets. This is the stylish way to deliver an invitation for your special event. The address goes on the outer envelope. The inner envelope serves as a place to specify who is invited by listing the individual names. No address is included on this envelope.
Your Thank You Notes should reflect your aesthetic, whether it's classic, romantic, minimalist or modern. The recipient of said note should know who it's from even before he/she reads a word.