Instead of running a file from an unknown source, use these official methods:
For older versions like .NET 3.5 (which includes 2.0 and 3.0), go to Control Panel > Programs > Turn Windows features on or off and check the box for .NET Framework 3.5. Summary: Should You Keep It? dotnetfx 365.exe
If you are looking for the actual .NET Framework to run an application, here is what you need to know: Instead of running a file from an unknown
A cloud-based subscription service that includes productivity apps like Word, Excel, and Teams. dotnetfx 365.exe
Enabled the creation of more responsive web interfaces.