A website is usually meant to be used on a personal device, PC or MAC where the keyboard has a Tab key. When using a website on a mobile device, which implies a touch screen, you usually don’t have that Tab key on the keyboard and you just click on the next field with your finger.
The same mechanism applies to IntuiFace, which is an interactive application creation tool, mostly meant for touch screens, and not a website builder
Having said this, it does happen on some mobile devices that recognize a multi-entry form that 2 buttons “next & previous field” are added on top of they keyboard. That could be a nice enhancement for IntuiFace and you should post this request in our Wishlist caategory.