PBS dependent from outside UK online application

Hi

I am applying for my wife visa. I choose apply for someone else in online application but could someone please advise who's the main applicant here ? If I am the main applicant in this case than why it doesn't show united kingdom under the location tab ? as I am in UK at the moment and i am filling it up on behalf of someone else

please urgently advise need to submit asap thanks

the Applicant is your wife and as she is applying for entry clearance she must be outside the UK. Note that she must personally sign the Declaration.
You are the Main Applicant and, as it happens, also the person who completes your wife's application.