Use thread for send sms

How do i use AJAX in app?

No I meant as in if you work with native app, all requests you do kind of work like AJAX, you stay on the page/view, but behind the scenes a request is made.

It really depends on native app framework you are using, and I really don't have any experience with any of them, but sounds like you want to find a solution that is non-blocking or runs on second thread so your main app can show the loading animation and not feel "stuck" while it waits response.