Hi @AshGary,
Usually, jams are hosted on itch.io, but they also use Crowd Forge and Discord too.
Crowd Forge is indeed very efficient for team building and Discord is useful to communicate. The idea with your Discord server is that it will features multiple channels. For example, you will have a "team building" channel, a "announcements" channel, a "project updates" channel, a "ressource" channel, etc. Moreover, at the end of the jam, it helps people to share their project with other participants and get feedback !
Here is a game jam's discord server example if you want to see what I'm talking about : https://discord.gg/x2n6PBE It was created for the HEART JAM (https://itch.io/jam/heartjam) and has since become a server for participants to share their day to day projects.