Wallet Basics
A wallet is controlled by keys.
A wallet app is only an interface. The actual power comes from the cryptographic secret that signs transactions.
Public Address
Safe to share. Used to receive XRP and view public ledger activity.
Seed / Secret
Never share. This controls the wallet and can move funds.
Signature
A cryptographic approval that tells XRPL your wallet authorized a transaction.
Simple example
Your address is the mailbox. Your seed is the master key. A transaction is a signed instruction. The ledger is the public receipt.