By default NuGet packages gets downloaded from the public feed of Nuget Package Source ( https://api.nuget.org/ ). However, there could be some scenarios, where you want to use some of your company’s internal NuGet Packages or some prerelease version of package. If you search them by just using adding nuget package, you won’t be able to get them. In these case, you need set up a custom NuGet source in Visual Studio.
Here is how you can create local Nuget source. First of all, Click on the “Manage Nuget Packages” from the Project Add Reference context menu.
By default, the NuGet Package Manager window will refer to the all package source located at “Nuget.Org” as shown in image below.
To Configure the local resource, click on the “Settings” icon. This will bring the “Options” dialog windows.
Navigate to “Nuget Package Manager” –> “Package Sources”
There you will only find the default reference to the nuget.org.
Now, Click on the “Add” / + Icon. to add a new source and click on the Update and Ok.
Now, again go back to Nuget Package Manager and then select the “New Source” as a local source for your local nuget packages.
Incase, there is any “Pre release” version of packages you want to search, you can select the “Include prerelease” check box.
Here after, if you search, it will always search packages from your local Nuget Feeds.
If you are using “Package Manager Console” make sure you are also referring the the customize source for the package reference.
Hope this helps . Refer to this article for further information