.NET Core - Generate Authentication Token for multiple APIS

I'm developing an application in .NET Core 2.1.

The application will have multitenancy features.

I'm building the project structure and will be:

AuthServer

API1

API2

API3

I want to generate a JWT token in the AuthServer and this token can be used in API1, API2 and API3 as authentication. I know there is IdentityServer4, but I find something very robust for something simple.

Does anyone have any idea how I can do this?