The relevant part of my Emacs configuration for notmuch is the
following:

#+begin_src emacs-lisp
(defconst notmuch-mark-deleted-tags '("+trash" "-inbox" "-archived" "-sent" "-spam")
  "List of tags to mark for deletion.")

(defconst notmuch-mark-removed-tags (cons "+rm" notmuch-mark-deleted-tags)
  "List of tags to mark for removal.")

(defconst notmuch-mark-spam-tags '("+spam" "-inbox" "-trash" "-sent" "-archived")
  "List of tags to mark as spam.")

(defconst notmuch-mark-flagged-tags '("+flagged")
  "List of tags to mark as important (flagged).")

(defconst notmuch-mark-shopping-tags '("-inbox" "+shopping")
  "List of tags to mark as shopping.
This is related to emails from stuff I buy online.")

(defconst notmuch-mark-financial-tags '("-inbox" "+finance")
  "List of tags to mark as financial.")

(defconst notmuch-mark-meeting-tags '("-inbox" "+meeting")
  "List of tags to mark as meeting.")

(defconst notmuch-mark-account-tags '("-inbox" "+account")
  "List of tags to mark an e-mail as accounts related.
That is, this e-mail in particular is something link a
confirmation of registering or something similar.")

(setq notmuch-archive-tags '("-inbox" "+archived")
      notmuch-message-replied-tags '("+replied")
      notmuch-message-forwarded-tags '("+forwarded" "+sent" "-inbox" "-trash" "-spam")
      notmuch-show-mark-read-tags '("-unread")
      notmuch-draft-tags '("+draft" "-inbox" "-sent" "-trash" "-spam")
      notmuch-tagging-keys
      `((,(kbd "r") notmuch-show-mark-read-tags "Mark as read")
        (,(kbd "u") ("+unread") "Mark as unread")
        ;; (,(kbd "c") notmuch-mark-complete-tags "Complete and archive")
        (,(kbd "d") notmuch-mark-deleted-tags "Mark for deletion")
        (,(kbd "R") notmuch-mark-removed-tags "Mark for removal")
        (,(kbd "f") notmuch-mark-flagged-tags "Flag as important")
        (,(kbd "s") notmuch-mark-spam-tags "Mark as spam")
        (,(kbd "S") notmuch-mark-shopping-tags "Mark as shopping")
        (,(kbd "F") notmuch-mark-financial-tags "Mark as financial")
        (,(kbd "M") notmuch-mark-meeting-tags "Mark as meeting")
        (,(kbd "A") notmuch-mark-account-tags "Mark as account")))
#+end_src

Best regards (and sorry for the long mail),

-- 
João Pedro de Amorim Paula
IT undergraduate at Universidade Federal do Rio Grande do Norte (UFRN)