Best answer: Yes, you can upgrade to Windows 10 from Windows 7 without losing files. You only need to use the Media Creation Tool to perform an in-place upgrade.
To make sure that the upgrade goes smoothly, make sure to upgrade using correct version. For instance, if you’re running Windows 7 Professional or Ultimate, make sure to upgrade to Windows 10 Pro. If you’re running Windows 7 Home, Home Premium, or Starter, then make sure to upgrade to Windows 10 Home.
Here’s a video with the walkthrough instructions to preserve your files after the upgrade:
You can find more details, in this guide.