Unfortunately, the pre-configured pages and the dialog boxes (modal windows) are not presented in the default configuration of the mobile application yet.
Detailed information about the mobile application interface (as well as information on how the edit data option works there) can be found in the Get started with the mobile app UI Academy article.
Depending on your business task, your can make up a business process with AUTO-GENERATED PAGE or PRE-CONFIGURED PAGE elements. Here are some more details on them:
Basically, the application does not support opening small dialog boxes, but you can use auto-generated page with any fields or buttons that you need. It can appear as a separate page but not as a small dialog box.
Auto generated page and pre-configured page will not be acceptable for our client since it will open as full screen. What we want to achieve is only as size as mini page or a dialog box.
How can we open a minipage in client code? maybe we can use mini page, upon clicking a custom button we will load a minipage.
Yes, that would be possible if you are ready to create this window using the development tools. Here are a couple of similar articles that will be helpful.
You can also analyze the the any minipage code and create a custom page that would open up upon your preferred conditions, as in your example upon clicking any button.
I found below dialog box with text field in BPM online after clicking the new email account. Same as below is our requirement, any idea how we can achieve this?
There are no basic tools in the bpmonline that would allow to open similar boxes. However, we suggest you to analyse the 'ModalBox' as well as 'ModalBoxSchemaModule' schemas code and develop your own dialog windows that would pop up under your preferred conditions.