In mobile, when entering text, anything under the textbox is hidden by the on screen keyboard. I was thinking of putting a "Submit" button under the textbox, but then I thought the user might not know to tap out of the textbox to dismiss the keyboard. Especially on iOS where there is no ENTER button.
So where would you suggest putting the "Submit" button? Should I assume the user does know how to dismiss the keyboard?
iOS has a Done link that lets the user hide the keyboard. It's also becoming common for webforms to have just one input field and button per screen, so that the CTA button stays accessible. You can also experiment with CTA buttons that are always in a fixed visible position on the screen.
You can put the SUBMIT BUTTON wherever you find it aesthetically good.
In my opinion: Take the example of Screen 1 - when you will enter the app the user sees a page with 4 fields and a button at the bottom and when he clicks on phone no. or email placeholder then the keypad appears(screen 2). So the user already knows where was the button before the keypad appears.
Note:
I prefer the button to be near the text placeholders as if our placeholders are at top and button at the bottom so there is a lot of white space between the fields and button.
When the user enters the login screen and if the button is near the placeholder it easy for the user to fill the fields and then click the button beneath quickly instead of scrolling unnecessarily towards the end of the page.
