If you have storage sense turned on in Storage settings, Windows can automatically free up space by getting rid of files you don't need, like temporary files and stuff in your recycle bin. Or, you can delete them manually.
Open the Start menu and select Settings > System > Storage.
Do any of the following:
To have Windows delete unnecessary files automatically, turn on Storage sense.
To delete unnecessary files manually, select Change how we free up space > Clean now.
To specify which files you want storage sense to delete automatically, select Change how we free up space, then select or deselect the check boxes for options under Temporary Files and Free up space now.
If you have photos, music, or other files that you want to keep but don't use very often, consider saving them to removable media, like a USB drive. You'll still be able to use them when the drive is connected, but they won't take up space on your PC.
Connect the removable media to your PC.
Open File Explorer from the taskbar and find the files you want to move.
Select the files, go to the Home tab, and then select Move to > Choose location.
Select your removable media from the location list, and then select Move.
If you've updated to the latest version of Windows 10, save space by turning on OneDrive Files On-Demand. You'll be able to get to your OneDrive files from your PC without having to download them all. See Learn about OneDrive Files On-Demand for more info.