The software keeps current and past documents in storage so that work in progress can be resumed at a future date. These can be seen in the Recent Document section when you start the software. 

There are two ways they can be deleted.

Within the software

• Start the software and Go to the Recent Documents.
•  For a single item right click or control click on it and choose Delete.     
• When you want to delete some of them then hold down the shift key and select the desired items then right click or control click and choose Delete.
•  When you want to delete all of them use the keyboard shortcut Apple + A to select all, then right click and choose Delete.
  

In Finder

The folder we want to delete is hidden by default in the User Library.

• To navigate there directly use this keyboard shortcut in Finder to show hidden files.
  Command + Shift + Period
• Then navigate to /Users/{user_name}/Library/Application Support/ReadirisPDF23
• Drag the Workspace folder to the trash and empty the trash

Using the Go menu

• In Finder on the Desktop click on the Go menu ► Go to Folder
• Paste in this text and then press the Enter key on your keyboard:  
  ~/Library/Application Support/ReadirisPDF23
• The ~ tilde at the beginning is important as that means the User Library instead of the System Library. 
• Drag the Workspace folder to the trash and empty the trash