Visual Studio for Mac has option to add extension from Visual Studio > Extensions...
From the Extensions window, if I search Specflow and I see nothing is there.
Is there any option to install Specflow extension on Visual Studio for Mac?
Here you may find some useful information;
Although SpecFlow team doesn't maintain their own extension for Visual Studio for Mac they have an amazing community created on at SpecFlow-VS-Mac-Integration.
In there,
Download Addin Visual Studio for Mac
You can download the addin here Release 1.11.3.0
Installation Visual Studio for Mac
To install, goto 'Visual Studio.../Extensions...' click the button on the far left saying "Install from file..." and select the mpack file from your hard drive.
The addin will install and you can now run and create specflow tests
Or,
Right-click on your project in Visual Studio, and select Manage NuGet Packages from the menu. Switch to the Browse tab. Enter “SpecFlow” in the search field to list the available packages for SpecFlow. Install the required NuGet packages.
There is no way to get specflow extension in visual studio for mac. You can think of vs for mac as a light version of windows vs, therefore there are almost no extensions at all.
However, you can use JetBrains Rider to install specflow extension, the only catch is that Rider is paid.
Links: