How many skydives do you have? Are you already an instructor in your home country?
More importantly, at what level is your current Mountain Dew consumption? Gotta be at at least 4 liters/day to qualify for the worldwide extreme instructor level.
What?? Are you going to judge this dude based on Mountain Dew consumption numbers? Everyone knows that's totally inaccurate, because he could have mad skillz and be doing quality consumption with coaching that puts him way ahead of the game. In fact, just switching to Code Red easily cuts the numbers in half, because it's waaaay more extreme. And that's not even taking into consideration any previous Red Bull experience.
To the OP: The worldwide instructor endorsement is just a hologram sticker that they put on your worldwide drivers license. I heard that the Karnage Krew website has them for sale.
My goal is to earn an instructors qualification in multiple extreme sports then work all over the world. Is there a worldwide certificate/qualification that will enable me to get hired as a skydiving instructor anywhere in the world?
No. Each nation has it's own governing body and requirements.
And it will take several years of experience before you will be good enough to earn an instructor rating. So you need to be in the sport for the long haul.