You can download IBKR Mobile app on your iPhone directly from the App Store.
1) On your iPhone tap the App Store icon.
2) Tap the Search icon (magnifying glass) in the lower right corner,
Figure 2
3) Tap in the search bar at the top, type IBKR Mobile. The search results should automatically appear below the search box.
Figure 3
4) Select the IBKR Mobile from Interactive Brokers LLC and tap on the download icon GET (if prompted, enter your Apple ID password or provide your FaceID / Fingerprint).
Figure 4
5) Once the installation has completed, tap OPEN to launch the IBKR Mobile app.
Figure 5
6) Tap Setup IB Key using QR code.
Figure 6
7) Type the alphanumeric string present below the QR code in the Activation Code field.
Figure 7
8) Tap Activate IB Key
9) You will receive a message confirming the successful activation of IBKR Mobile Authentication (IB Key). Tap DONE to complete the procedure
Figure 9