Your funds are not stored in Phantom. Your balances and transaction history are recorded on the blockchain, and access to them is controlled by cryptographic keys that only you hold. Phantom stores those keys locally on your device and uses them to sign transactions on your behalf. You access them using your Secret Recovery Phrase, individual private keys, or a Google or Apple account protected by a PIN.
Because your keys never leave your device, no one, including Phantom, can access or move your funds without them.
Warning: Do not share your Secret Recovery Phrase or private key with anyone. If someone has access to either, they will have full control of your wallet. Phantom Support will never ask for your recovery phrase or private key.