What is Paid editing disclosure?
Also called: WP:PAID
Short answer
A Wikimedia Terms of Use requirement that anyone compensated for edits discloses their employer, client and affiliation.
Disclosure goes on the editor’s user page, on the article talk page, or in edit summaries. It is a condition of use, not an optional courtesy.
Undisclosed paid editing is treated as a serious violation. Accounts are blocked and the articles are examined — which puts the subject in a worse position than having no article.
Why it matters
Any Wikipedia service that offers to work "discreetly" is offering to break the rules on your behalf, with your page as the thing at risk.