By default, no permissions need to be configured — server owners can use it out of the box (hot-reloading plugins may cause default permissions to be invalid)
For types mentioned below that you're unsure about, use tab completion in lower versions; 1.12+ will automatically provide hints

Permissions

Permission	Purpose	Default Owner
playerSignIn.reload	Reload plugin	op
playerSignIn.convert	Convert data	op
playerSignIn.signIn	Open sign-in GUI	true
playerSignIn.default	Default sign-in reward group	true
playerSignIn.giveSignCard	Give retroactive sign-in card (1.2.0+)	op

Commands

Command	Purpose
/psi reload	Reload plugin
/psi convert [mysql/sqlite]	Convert data
/psi signIn	Open sign-in GUI
/psi giveSignCard [player] (amount)	Give retroactive sign-in card (1.2.0+)

[] Required () Optional