Readable PDF 
Open PDF File
To open a PDF document click on + button and choose file. Also, you could drag and drop a PDF document into app's body/view. In addition, you could select PDF document then right-click and choose Open With option and select Readable PDF app. Another option is to set Readable PDF App icon in Dock then drag and drop PDF documents on top of app's icon. One more option, set Readable PDF app as a target within print dialog as shown on video Print Option from Safari - among other ways to open a PDF document.
Thumbnails View
Shows and hides thumbnails view of current open PDF document. Easily skim through document or use it to navigate PDF file.
Outline
Option that allows one to jump among outline topics on PDF documen
Read Out Loud
Option to start reading out loud text on PDF document. Depending on previous action, play button will either start to read from paused word or from the beginning of current page if previously clicked stop button.
Pause Reading
Momentarily stops reading text on PDF document. Pause button stops reading at current reading word, it would continue reading once play button is clicked again.
Stop
Option to stop reading out loud and reset cursor to beginning of page. This option resets reading location within page. Another way to choose a starting reading point is by selecting text then click play button.
Highlighing Color
Option to allow one to choose highlighting color to use when reading words out loud. There are both predefined colors as well as a custom option to select a preferred highlighting color.
Auto Scroll
Auto scrolling while reading out loud. Scroll is enforced according to reading word. Disable this option when exploring PDF document. This option allows page of document to be focus while reading.
Recording
Listen your readings while jogging or relaxing by converting PDF document to a sound file. There are three options available: All, Single, and Range. All option generates audio file of entire PDF document. Single option allows one to chose any particular page to be converted to audio file. Finally, Range option lets you choose consecutive pages from which audio file is generated.
Voices
Choose from many voices and languages built-in macOS. There are more voices that one can download using System Preferences > Accessibility > Speech
Voice Rate
Choose speaking rate of chosen voice. Five different speaking speeds to choose from according to level of own confort. When selecting recording option to generate audio file, voice and rate are taking into account.
Saved List of PDF Files
Quick option to load saved reading PDF documents and their progress. This option is not the same as Open Recent option under File menu.
Save Option
Select this option before closing app to remember reading progress of PDF document. This allows app not oly remember PDF document but also saves your reading progress.
