As DAML is private network, so the new users / parties are not present initially (except it is added during genesis creation), so is there any other way to onboard new users / parties after the genesis configuration? If yes is there any reference available?
You can add users and parties to a ledger once it’s created in two ways; via the Daml Hub console in the identities tab of the ledger or using the API. Docs on how to do it in the console are here, the user API docs are here and the party API docs are here.
I hope that helps,