
You can see the following VSIX installation prompt.

On the left, click the Online tab and type “Xamarin Extensions” in the search box. In Visual Studio 2017 or lower, go to Tools -> Extensions and Updates Navigate to Extension -> Manage Extensions and open the Manage Extensions.The steps below assist you to how to install the Syncfusion Xamarin extensions from Visual Studio Manage Extensions. Visual Studio 2019 or lower Install through the Visual Studio Manage Extensions

You can either use the Visual Studio to install it or go to the Visual Studio marketplace to download and install it. In below Visual Studio marketplace link, Syncfusion publishing the Xamarin Visual Studio extension.
