what is authentication used for code example

Example 1: which authentication you used

I use bearer tokens in my current framework.
I send a get request to special API endpoint by providing valid 
credentials, then it will return Access Token. I use that token 
in my request header and access other API endpoints

Example 2: what is authentication

Authentication is the process of recognizing a user’s identity. 
 It is the mechanism of associating an incoming request 
 with a set of identifying credentials. 
 credentials provided are compared to those on a file 
 in a database of the authorized user’s information 
 on a local operating system 
 or within an authentication server.