When user select any value from drop down, additional field are get visible without any prior warning. This change of context is disorienting for visually impaired and cognitive impaired user.
The drop down values are domestic account, international account.
if user select the domestic account, then sort code, account number field will be displayed. if user select international account, then account number, currency field will be displayed.
How to provide an instruction to the user beforehand and describe this behavior (that focus move to sort code or account number) ?
<label class="" for="">
<input type="" name="" value="listbox" aria-label="choosing a key format will cause additional fields">
It could be as simple as having a line of visible text (instruction) before the dropdown that says "choosing an account type will cause additional fields to appear". (You may want to word it better than that. Check with your designer or content specialist.)
Having that instruction line would also fulfill WCAG 3.3.2 Labels or Instructions in addition to the original WCAG 3.2.2 On Input you asked about. (Those two WCAG numbers look very similar.)