Installing .NET Framework 3.5 on modern systems like Windows 10 and Windows 11 is a common requirement for running older software and legacy applications. While Windows usually prompts for an internet-based download, you can use an offline installer or local installation media to complete the process without an active connection. Direct Download Links (Official)
If you want a standalone file to keep on a thumb drive, you can download the redistributable package directly from Microsoft. Visit the Official Microsoft Download Center. Installing