Accessibility work helps more people use a website and can expose problems that affect everyone. Commission a review around real tasks rather than asking only for an automated score.
Define the scope and target
List the page types and journeys in scope: navigation, search, forms, account access and key documents. Agree on the standard and level the specialist will assess against. Do not describe the whole site as compliant based on a small sample.
Provide designs and component documentation if available. Shared components matter because one navigation or form issue can affect many pages.
Combine automated and manual checks
Automated tools can identify some issues quickly. Manual review is still needed to assess keyboard operation, meaningful labels, focus order, error recovery and how the page is announced by assistive technology.
Include a person who can explain the effect of each finding. A developer needs more than a rule number to fix an interaction correctly.
Make remediation actionable
Ask for a backlog with the affected page or component, reproduction steps, user impact and a proposed remedy. Group repeated issues at component level so the team fixes the underlying pattern.
Test fixes in complete journeys. A dialog might look correct while trapping keyboard focus, and a form may announce an error without showing how to correct it. Request a second review of the most important fixes.
Use the W3C WCAG quick reference to identify the applicable criteria. Your engagement should state the scope of the assessment and the evidence collected, rather than promise universal certification.
Find an accessibility-aware product designer and developer who can work together on implementation and verification.