Many PDFs are simply images of text created by scanning hard copy documents. These PDFs should be converted into searchable text, which typically requires conversion into text using optical character recognition (OCR) software. Text converted with OCR will usually need editing.

The #NoMouse Challenge is a global effort to raise awareness about accessible web design. Try using your website without a mouse. Use the keyboard instead. Is it possible to access all features and operate all buttons, sliders, and other controls?

https://nomouse.org