The orders are being sent to Amazon.com, Inc., ByteDance Ltd., which operates the short video service TikTok, Discord Inc., Facebook, Inc., Reddit, Inc., Snap Inc., Twitter, Inc., WhatsApp Inc., and YouTube LLC. The companies will have 45 days from the date they received the order to respond.
Here is the actual more detailed order:
https://www.ftc.gov/system/files/documents/reports/6b-orders-file-special-reports-social-media-service-providers/6bs_order_os_final.pdf
The companies listed: Amazon, ByteDance (who operates TikTok), Discord, Facebook, Reddit, Snap Inc (SnapChat owners), Twitter, WhatsApp, and YouTube.