How do SMM panels source accounts?

Are most of them using browser automation, phone farms, or hiring people to create them manually?

Some panels buy bulk accounts from third-party sellers who already made them.
Others scrape emails or social IDs and convert them into full profiles.
A few still use bots plus rotating proxies to automate sign-ups.
Many combine buying, scraping, and automation for a steady flow.

Most of them just connect API from child panel.