You have to include the library at the root-level _Imports.razor file through the @using directive.
You can consume a library in either of two ways:
If the MyComponentLib is the component library and MyComponent is the component name, those are consumed like in the following.
<h1>Hello, world!</h1> Welcome to your new app. <MyComponentLib.MyComponent />
@using MyComponent <h1>Hello, world!</h1> Welcome to your new app. <MyComponent />
Refer to the link Consume Blazor a library component.Permalink
You have to use the following command to include a Blazor component library application.
dotnet new razorclasslib -o MyComponentLib1
Refer the below documentation link for more information.Permalink