What is the difference between header Authorization and X-Authorization?

Question

HTTP headers

Tell me, what threatens the use of headers to transfer the X-Authorization token instead of Authorization. The essence of the problem, I send a request to the server with php, I write Authorization in the headers, the problem is that they can only be pulled out by the apache_request_headers function, and if PHP does not work on Apache, how can I get this token? I solved this problem by sending it with the X-Authorization header, which is easy to read in the $_SERVER['HTTP_X_AUTHORIZATION'] variable, what could it be?
And the second question, why is the word Bearer written in the authorization header for transferring a token? What does it mean? (Bearer eyJ0eXAiOiJ......fVbY-A0) What happens if you remove it and transfer only the token itself?