also. depending upon the “use” of the sigil:
whether it is to “radiate” an affect from the paper-document, vs
affect/influence the receiver/reader of the document ‘directly’ via the sigil, ie not thru the paper-doc, vs
influence/affect the situation, including any-all others involved in the sit… again not the paper so much, but to Assist what the paper is trying to achieve.
-this can be a sigil to “spell” nudge things to end up a certain way… or could be to change your own state of mind while your “write-edit-update” the doc (do you want the sigil-influence to inspire-inform you as writing, or just write whatever “boilerplate-doc” and the sigil is to be make the reader love it)
-that last part reminds me of the saying about Greek Philosophers: there was one who was known to give a speech and people stood and cheered (if being cheered, and having your presentation, is the goal), vs another who when he gave a speech… people stood and marched… (no comment, no cheering, but they acted- the result not to win the “hearts&minds” but to cause a certain mass-mob action)… could be more subtle of “inserting” a v-meme, where the listeners/readers don’t think much of what they read, even forget all about, but their actions/thoughts seem to indicate they were influenced by…
in short- one’s magic should be in the everpresent-moment influencing-shaping whatever aspect of the sit that you are Seeking (and Able) to affect, and not “necessarily” be linked via some covert-substance/
(by “necessarily” meaning, one could choose that medium-channel, but those that seem to indicate that a “slight modification of chance can occur, by subliminally attacking another” might seem to question if those are magically affecting or just ‘mental’ or just coincident -ie in a court case, one needn’t send a letter with “powder” or other symbols, to jurymembers/judge/or opposing party to have the case (?)
[to respond to what might be the question beneath the question, rather than how to actually embed a sigil… what might be the reason to seek that? is the sigil- or other magick- being applied to the sit…]
to riff upon what -TWF- wrote, also watermarking an image, for print or digital… if seeking physically add (clear draw upon~ invis ink)
or “embedding” in a picture (if a photo or design is included- digitally vs print) then every-other line (ie how info can be encrypted in picts, also the GIF “moving pict” aspects)… or the approach-thought of “imagining” a symbolic-eform that is attached and stays with the paper (but all this as above in terms of purpose).