Tap "Location" and a list of available locations for your bookmark will drop down. You can also create a bookmark using the share icon on the ... and flip the switch to green to turn sharing ...

You can drop a pin on your iPhone by pressing and holding your finger down on any blank space in the Maps app. Once you've dropped your pin, you can share it, get directions to that location ...

Of all the locations on the desktop ... Just click on the Dropbox icon, drag it towards the tiny arrow pointing upwards until the pop-up window appears, and drop in the icon.