Could you please tell me, when you're writing a thank you letter as a couple should you sign your own name first or your partner's name first.
Usually, the person who writes, not types, the letter signs his/her name first. If both people write the letter, have equal input on what the letter should say, then, the person who is closest to the recipient of the letter writes his/her name first. If both people know the recipient well, then, and according to the rules of traditional practice, as in Mr & Mrs ..., the male's name comes first. If there are two males or females, then either name could come first.
Does that help?