Are you referring to using the Dropbox API? With the API, your app can choose what and when to upload. When it does want to upload something, it can then use the API calls e.g., /files_put to do so. After that, it can perform any cleanup necessary. That's all up to your and your app though.
We love to learn from the educators who use Dropbox. Whether you teach kids, teens, adults or a combination of all three, we want to know what apps and integrations you use with Dropbox to help with teaching. Which of the ones below is your favorite, or most used tool?