SumatraPDF makes it easy for you to open current document in a different program.

For example, if you also have Adobe Reader installed, you can use File menu to easily open PDF document you're viewing in Adobe Reader. We auto-detect a bunch of popular apps (Adobe, FoxIt, PDF X-Change etc.).

You can also add custom readers using advanced settings.

To configure an external reader:

Here are the relevant settings:

ExternalViewers [
  [
    CommandLine =
    Name =
    Filter =
  ]
]

An example could be:

ExternalViewers [
	[
		CommandLine = "C:\\Program Files\\FoxitReader\\FoxitReader.exe" /A page=%p "%1"
		Name = Foxit &Basic 3D view or Review Text
		Filter = *.pdf
	]
]

CommandLine is a full path of executable that opens a given type of the file.

"%1" will be substituted with a full path of the current document.

You can also use %p current page number. Not all viewers support page number.

Name will be displayed in File menu.

Filter restricts which files can be opened by the reader. For example: