1. As a general rule, you should remediate from the original source file. For example, find the original Microsoft Word file from which a PDF was created. 
2. Using the latest version of the software will offer the best source of accessibility support. Go to Software.berkeley.edu to download the latest versions of your application.
3. If you have the original source file, review the Microsoft Word 2016, Windows 10 Remediation Tutorial and/or the National Center on Disability and Access to Education Cheat Sheets
4.  If you are NOT working with the original source file, then the Adobe Acrobat Make Accessible Wizard and Leverage Adobe Acrobat's Make Accessible Feature are relevant tutorials to review.