Get Kubernetes pod logs (multiple files) with Loki

We are gathering the logs from our services because are taken from the Standard Output, but we also have more files with logs, and we don’t know how to extract them to our Grafana instance.
The components are an EKS Kubernetes cluster with the promtail pod (created with Helm) ingesting the logs to Loki.

We didn’t find information about how to do it, do you know if it is possible to do it and how?

Thank you!!