Use the Microsoft Gacutil tool at https://docs.microsoft.com/en-us/dotnet/framework/tools/gacutil-exe-gac-tool to install a DLL into the Global Assembly Cache (GAC). For more information, refer to "How to install an assembly into the Global Assembly Cache in Visual C#" at https://docs.microsoft.com/en-us/troubleshoot/dotnet/csharp/install-assembly-gac.