Some keys on the keyboard are hot keys, which greatly improve your performance of manipulation with PDF files while reading.
File Manipulation
Ctrl+O - Open a PDF file
Ctrl+S - Save a PDF file as other file formats
Ctrl+W - Close a PDF file
Ctrl+P - Print a PDF file (print dialog appears)
Page Manipulation
Home - Go to the first page
End - Go to the last page
PageUp - Go to the previous page
PageDown - Go to the next page
Ctrl+G - Go to a certain page (a dialog prompting user to enter a page number appears)
Ctrl+B - Add a smart bookmark to the page in view
Zoom
Ctrl+T - Zoom To a percentage (100%, 125% et al)
Insert - Zoom In (in Continuous View Mode, + works as well)
Delete - Zoom Out (in Continuous View Mode, - works as well)
Rotation
F5 - Rotate clockwise
F6 - Rotate counterclockwise
Snipping Tool and Copy
Ctrl+C - Copy selected area or entire page as text to Windows clipboard
Ctrl+I - Copy selected area or entire page as an image to Windows clipboard
View Mode
F1 - Continuous View Mode (this feature is only available in the PDF Reader Pro version)
F2 - Fit Width
F3 - Fit Page
F4 - Actual Size
Slideshow
F10 - Start slideshow for presentation
Eyestrain Reduction
F7 - Night Reading Mode
F8 - Low Blue Light Mode
F9 - Airplane Reading Mode
Find & Search Text
Ctrl+F - Search text in PDF files (this feature is only available in the PDF Reader Pro version)
Miscellaneous
F11 - Maximize the window of PDF Reader to cover entire Desktop.
Ctrl+Q - Exit the PDF Reader software (even if in Slideshow)
C - Switch between Continuous View and Fit Page View (this hot key is only activated in the PDF Reader Pro version).
Z - Switch among Continuous View, Fit Width View, and Fit Page View (this hot key is only activated in the PDF Reader Pro version).