Trezor Hardware Wallet (Official) | Starting™ Up Your Device
The basic process is straightforward. After setting up the device, the wallet generates or imports the necessary wallet information according to the supported setup process. The device then helps protect the private keys used to authorize transactions.
When a user wants to send cryptocurrency, compatible software prepares the transaction. The hardware wallet receives the relevant transaction information and displays important details for verification. The user can then approve or reject the transaction using the device.
The private key itself is not intended to be exposed to the computer simply because the computer is preparing a transaction. This separation is one of the fundamental concepts behind hardware-wallet security.