I have an author role, i want user with an author role connect to Strapi app for add content for example.
I found http://localhost:1337/admin/auth/login
for connect to admin panel of Strapi but this for Administrator.
What's url for user with author role ?
Currently it is not possible since "front-end users" are separated from administrators.
This is a good read on the concept of Administrators & front-end users, it will give you a clear understanding on these concepts & answer all your questions.
Custom admin UI is in the road-map under 3 tasks:
Administration Menu
Users, Roles & Permissions
Also - Field-level permissions
So maybe by 2021 :)
What you can do to limit permissions: