To use the desktop app or the web client without having to scan the QR code each time, you can set a session password.
Enter a session password in the desktop app or the web client before scanning the displayed QR code with your mobile device. To use the desktop app or the web client the next time on the same computer, you can simply enter this password (instead of scanning the QR code again).
With Android devices, it’s also possible to use Threema if your mobile device isn’t present (provided it’s connected to the Internet and a session password has already been set on the computer). On iOS, the mobile device needs to be unlocked, and the Threema app must be running in the foreground (cf. this FAQ entry).
The different sessions are listed in the mobile app, where you can remove and rename them.
