First off, there is NO certificate that is issued by any government agency certifying compliance. Your only proof of compliance is documentation that accompanies your accessible PDF.
Luckily, you have found a reputable document remediation service, Accessibility In Mind, and you can rest easy. When we complete any remediation we provide our clients with documentation of the work performed, which includes accessibility reports from one or more sources:
- Acrobat 11 full accessibility report: This is the first stop, a report that shows compliance in 32 of 32 categories, and proves technical compliance.
- PAC Accessibility Check: The PAC program provides a fast way to test the accessibility of PDF files. PAC supports both experts as well as end users conducting accessibility evaluations, and is based on the Matterhorn Protocol. Matterhorn was designed to foster adoption of PDF/UA by providing a set of 31 Checkpoints and 136 Failure Conditions that help software developers exchange detailed information on PDF/UA conformance and create software to make it easier for document authors to create fully accessible PDF files and forms.
- CommonLook by NetCentric Section 508 Reports: Common Look is considered the "gold standard" for accessibility reporting, and is recommended by Health & Human Services (HHS) and is generally accepted for all government contracts.