Joaquin,
are you looking for this: https://www.microsoft.com/en-us/software-download/windows10
Click "Download tool now" to download MediaCreationTool1909.exe
Run MediaCreationTool1909.exe and pick your language/edition/architecture.
The procedure will take a while but you should finally get the ISO/USB or be able to upgrade this PC.
Regards,
AnZa