If you are following an old guide or video telling you to download 4.0 manually, – that advice is obsolete and dangerous.
It looks like you’re asking for a of a search query or a potential download for ".NET Framework 4.0 version 4.0.30319 on Windows 10 64-bit" .
Do not download “.NET Framework 4.0 v30319” from anywhere. Instead, turn on .NET 3.5 (if needed) and ensure .NET 4.8 is installed via Windows Update or Microsoft’s official download page.