moving a door

Cait

Hi all. I'll be moving into a house where the entrance to the 3rd bedroom/study is in the dining room. I'd like to change that so you enter the room from the hallway. Why the builder put the doorway in the dining room is beyond me. Neither wall is loadbearing.
I've seen diy advice on making a new doorway but nothing on how to close up an unwanted doorway. Should I cut out the remaining drywall above the doorframe and add one piece of drywall in the opening? I know I'd have to add a 2x4 floor plate but should I also add a stud and noggins?
Thanks!
Cait

Bonus

I've never heard of a "noggins", but , yes, cut the rock to the ceiling, add studs @16"o/c and re-rock.

2pyrs

All I did was remove all the trim and door frame, add some 2x4s to fit the space, tape and some mud, paint,baseboard done.

2pyrs