No web application should ever be made without a user registration and authentication feature. Authentication gives permission for a user to access the proper resources or services. The fundamental property of HTTP is a stateless protocol that contradicts authentication, which works to keep the state of the user.
JSON Web Tokens (JWTs) help get around the contradiction between HTTP and authentication. The backend of the Angular app authenticates the JWT, validates the user, and grants them access. To make this happen, the app talks to the backend to generate a token, which then is communicated to the Authorization header to verify the token. You can also address this issue with session-based authentication and cookies. This means that the backend will create a “session cookie,” which provides a process for the server to confirm the user’s identity.