How can I export/import settings of Sublime Text 3 from one PC to another using Windows?
The best way is to sync the User directory, there are multiple available ways to do this - dropbox, git and manual ways.
Installed packages are registered in Package Control.sublime-settings, which is located in the user folder as well, thus, it does not require you to sync anything besides that. A pretty good guide to syncing can be found here.
You also may wish to check out this package.
For me (Windows installation) transferring all the content from old installation - AppData\Roaming\Subime Text 3, to new installation - AppData\Roaming\Subime Text 3, does the job. All the packages and UI settings are transferred and are working correctly.
None of the manual efforts are needed now (I think). Both sublime text (ver 3) and visual studio code (if anyone cares) have extensions that do this for us.
For VS Code -https://marketplace.visualstudio.com/items?itemName=Shan.code-settings-sync
For ST3 - https://packagecontrol.io/packages/Sync%20Settings
With a few clicks like generating token and configuration, one should be able to easily port the settings from any machine (Win, OSX, Linux) to any machine.