There are two ways in which free uploading works. Users can either upload files to websites that host files for free or to free cloud storage services.
If a user uploads a file to a file hosting website, he receives a URL to access the file at a later date. Because such websites generally make money by also offering premium services at a cost, using them for free may have certain restrictions. They often restrict the user from uploading large files, downloading multiple files at once or downloading more than a predetermined amount of files in a day. Likewise, when using them for free, these sites usually delete files if no one downloads them for a few months.
Cloud services, however, usually have fewer restrictions. Although they also profit on premium subscription plans, cloud storage service providers often allow users to upload large files, download multiple files simultaneously and access as many files as desired. In addition, users can upload and store files from devices automatically. For instance, iPhone users can configure iCloud to automatically upload certain files for free.
Because cloud storage services require registration, users do not use links to access their files; instead, they log in to their accounts or use standalone applications. Such applications may even come as a part of the operating system, as in the cases of OneDrive in Windows, and iCloud in Mac OS X and iOS devices.