.vlk extension, is your project file you can edit in Valkyrie editor.
.vpk extension, is your compiled executable file that can be run if Valkyrie editor is installed on your computer, or with the We3D iOS app on mobile.
.exe extension, is your compiled executable file that can be run on any Windows computer (in Valkyrie editor you can choose between exporting your project as a vpk or an exe).
I have purchased a license however the free version watermark is still displayed on my exported projects. What gives?
A common mistake is that you did not paste your token correctly in the export panel. Make sure that you did not insert any space before or after the token.