Hair loss... How to start managing hair loss?

hello.

These days, when I wash my hair, dozens of hairs fall out, and my heart sinks.
It seems like the crown area is looking more bare than before, and I feel like I can't leave it like this, so after much thought, I'm posting this.

Actually, this is my first time managing hair loss, so I'm not sure where to start.

What hair loss treatments are available at the clinic?

I'm curious about the principle, how much pain it has, and how effective it is.

I heard that there are injection methods and laser treatments, but is there a treatment that is easy for a beginner like me to receive?