Jess Thompson from the Washington State Board of Community and Technical Colleges (SBCTC) hosted a Webinar in February 2018 on Accessible PDFs. This webinar focuses on the various features available on creating PDFs using Adobe Acrobat Pro.
Lynda.com - Acrobat DC: Creating Accessible PDFs (check with your institution/agency to see if you have a license for Lynda.com or check with your local library)