This is one of four achievements you get by playing through MyCareer mode and accumulating points -- in this case -- Virtual Currency (VC) to spend on making your character better.
As WWEADDICT4LIFE said, you need a total of 935,000 VC in order to complete these achievement.
You gain 1,250 VC after you complete the tutorial until you get promoted to Raw. Then you earn 2,500 VC per match, no matter how good or bad you do. As an experiment, I started a match. Then, without doing anything, I went to the main menu and quit. Sure, I lost the match, but I still got my 2,500 VC.
NOTE: You can only use them if they're on the same side you're on (you both need to be face or heel, one or the other, not both).
This is how much each manager costs:
FACE: This manager will cheer you on and help your chances of winning.Eva Marie: 5,000 VC
Brie Bella: 5,000 VC
Layla: 5,000 VC
Paige: 5,000 VC
Rosa Mendez: 5,000 VC
Natalya: 10,000 VC
HEEL: This manager will distract the referee and opponent during a match.Alicia Fox: 15,000 VC
Cameron: 15,000 VC
Emma: 15,000 VC
Naomi: 15,000 VC
Tamina: 15,000 VC
Lana: 30,000 VC
Zeb Coulter: 150,000 VC
Summer Rae: 320,000 VC
Paul Heyman: 320,000 VC
NOTE: You or your opponent can get DQ'd if your diva manager gets attacked, even by accident.
If you're only going for this (and/or the "I am the Best" achievement) you can just quit every match and still get the 2,500 VC.
Be sure to start a rivalry at the beginning of the month so you don't lose out on VC!
NOTE: If you're grinding all four achievements, it's better to get "Untouchable" and "I am a Wrestling God" out of the way first since you get significantly less SP if you lose.
These are the other three achievements you get by leveling up your character:
The Untouchable achievement in WWE 2K16 worth 265 pointsMyCAREER - Get an overall value of 95 or more. The I am the Best! achievement in WWE 2K16 worth 387 pointsMyCAREER - Purchase all skills that can be purchased.