How can I put the sublabels at the top of the field?

how do i put first name, last name, area code, phone number on top of input box instead of bottom

These are called sublabels so they are placed at the bottom of a field by default.

You may re-position them using CSS:

.form-sub-label {

   position: relative;

   bottom: 45px;

}

Here's where/how to inject CSS codes:

Complete guide: How-to-Inject-Custom-CSS-Codes

RESULT: