At the moment this is only possible in Android phones that are NFC enabled. Yoti will detect whether it is NFC enabled, but if not, you can enable it from your phone settings.
After you have scanned or taken the photo of your passport, you will be asked to place your phone facing up on top of the back cover of your closed passport. The scan of your passport chip will start automatically and will only take a few seconds. The scan will not take long but please be patient - coming out of the app or taking your phone off the passport will stop the scanning process. You will receive a success message once the scan is completed.