Hi @DJM54, welcome to our Community!
You mentioned that you have a desktop, and a laptop among the devices that might be using Dropbox, so let's start with that.
In order for you to uninstall our desktop app, you'd need to follow the steps mentioned here. Uninstalling the app, won't delete the Dropbox folder, and the content you have there, unless you choose to delete the folder after the installation.
One thing to keep in mind is to disable Computer backup, in case this is a feature you use on your end.
In regards to your mobile, you'd need to check the apps that you have installed there, and remove Dropbox from there. Usually you can do this if you long-press on the app's icon until the app shortcut gives you the option to remove it.
Let me know how this goes!