Grabit tells me to link it to Dropbox in Preferences?

jbhatstl wrote:

How do I link the the two?

Both of these are third party app— the developers sites have a support page and may well answer your question. FAQ is always a good first look.

Off the top of my head I would suggest looking at the :

Dropbox>Preferences

and

Grabit>Preferences

macOS Catalina has increased it security, and some restrictions can be over come giving Full Disk Access or File& Folder Acesss on an app by app bases.

>System Preferences>Security&Privacy>Privacy

Unlock the padlock lower left in the preference pane to make changes

Change Privacy preferences on Mac - Apple Support