What happens when you upload a PDF online

When uploading a PDF online, the file often leaves your computer and travels to a server, where it's processed and then sent back. This is the default behavior for many free PDF tools. It's not a scandal, but it's often invisible. Be aware of the wording on these sites, as 'your files are safe with us' and 'your files never leave your device' have different meanings. Consider the implications for sensitive documents.