Dropbox: NextCloud https://nextcloud.com/
Nextcloud is a suite of client-server software for creating and using file hosting services. It is functionally similar to Dropbox, although Nextcloud is free and open-source, allowing anyone to install and operate it on a private server. In contrast to proprietary services like Dropbox, the open architecture allows adding additional functionality to the server in form of applications and enables the user to have full control of their data.
here is the docs on how to install nextcloud https://docs.nextcloud.com/server/12/admin_manual/installation/source_installation.html