Start with who approves the work. If clients need to review proofs without becoming full users, Teamwork.com is the cleaner fit because external approvers do not need a Teamwork.com account. The trade-off is that its Free plan is limited to 5 projects and 5 users.
Separate proofing from task approval. ClickUp supports comments on images, video and PDFs, which is useful for creative review, but its approvals are more status-based than a dedicated approval task model. Free Forever and Unlimited include 100 proofing uses; Business and above include unlimited Proofing.
Check the plan before you design the workflow. Asana approval tasks and proofing sit on Advanced, Enterprise and Enterprise+ plans, not Starter. That makes Asana a tidy internal signoff tool, but the useful approval features may cost more than the headline Free, then $10.99 entry suggests.
Use monday.com when the process is visual. A board can run Draft → Internal review → Client review → Changes requested → Approved, with file annotations, versioning and permissions around the work. The catch is that monday.com is better as configurable approval workflow software than as a formal proof-approval system.
Do the seat maths before rollout. No per-approval transaction fee was found in the official pages reviewed, but seats, guest access, proofing limits, storage, automations, taxes and annual prepayment still change the real cost. monday.com paid plans start from 3 users, and displayed prices do not include tax.
Make final approval unambiguous. Teamwork.com marks a proof as approved only when all invited approvers have approved it, which helps with multi-stakeholder client signoff. The downside is that one slow approver can hold the whole proof in limbo unless someone owns the chase.