You've delivered, the client said "looks good", then three weeks later they come back with "actually, can we change one thing?". Without an explicit sign-off, there's no clean ending. The sign-off turns a vague "looks good" into a clear agreement.
Why a sign-off
A sign-off is the client's explicit approval of the final deliverable. It marks the end of the revisions included and the start of what becomes new work.
It protects you (you know when to stop), and it reassures the client (they know it's approved). Everyone gains clarity.
Make it simple: a button, not an email
Don't ask the client to "reply to approve": you'll be waiting for days. Give them a button. A delivery page with a clickable approval gets you an agreement far more often, and far faster.
xFer builds this button right into the delivery page: the client approves in one click, and you get the confirmation instantly.
Frame revisions around it
Announce the number of revisions included from the quote onward. Before the sign-off, the client asks for their adjustments; after it, it's new work. The line is clear.
A framed change request (specific, in the same place as the delivery) avoids scattered feedback and misunderstandings.
Track the approval
Keep a record of the approval: who, when, on which deliverable. If a disagreement comes up later, you have a clear point of reference.
When the approval happens on the delivery page, that record is automatic: you don't have to dig through your emails.
In short
Ask for an explicit sign-off, make it clickable, frame revisions around it, and keep a record. You close your projects cleanly, with no grey area and no endless rounds.