Plugins & mods
Plugins and mods are two different things. Plugins run on Paper and its relatives and your players install nothing. Mods run on Fabric, Forge, NeoForge or Quilt, and everybody who joins needs the same mods in their own game.
The panel shows the Plugins tab or the Mods tab depending on the server type you run, never both. The articles below walk through both.
Plugins & mods articles
Delivery: most servers are handed over instantly and run within seconds of payment, the rest follow within 60 minutes during the day and within 12 hours at night.