Authentication on external ql

Hello,
I’m trying to connect my frontend to my backend. The backend with its query is on another server and therefore needs authentication. My frontend is just a Next.js framework hosted on a CDN. Inside Next.js I want to fetch the data with Apollo. How can I send the authentication, consisting of username and password, to my backend? I use Kirby QL for my backend: GitHub - getkirby/kql: Kirby's Query Language API combines the flexibility of Kirby's data structures, the power of GraphQL and the simplicity of REST.

Thanks in advance
J