What a wallet actually is

A wallet is software or hardware that shows balances from the ledger and uses your keys to sign (approve) transactions. The coins are recorded on the ledger, not “inside” the app icon.

Delete the app and the funds still exist on the ledger if you still have the seed/private key — you can open another wallet. A fake wallet screen can still trick you into signing a bad send.

A wallet does two jobs. First, it reads. It asks a server what the ledger says about your address and shows you the balance. Second, it signs. When you tap send, it builds the transaction, shows you the details, and uses your private key to sign it once you approve.

After signing, the wallet passes the signed transaction to the network. From there, the wallet is just watching: the network decides whether it is valid and records the result on the ledger. The app never holds the coins. It holds, or can reach, the key that controls them.

Real example: a hardware wallet is a small device that keeps the key inside. When you send, your computer passes the unsigned transaction to the device, the device’s own screen shows the address and amount, you press its button, and only the finished signature comes back out. Even if the computer has a virus, the key stays inside the device. That is why checking the device’s screen matters. Source: Cryptographic Keys.