Defensive backs often get them from interceptions but it's possible for other players have forced fumbles, strips and blocked kicks.
I also believe that this could be very subjective, however, I will try to apply some logic to find a best available answer.
To take a 2014 approach, and looking at the statistics through the first three weeks of the season, it appears defensive backs may have the most influence on turnovers, at least during this season.
To explain, and according to ESPN.com statistics regarding forced fumbles and interceptions, there are 8 players with two or more recorded interceptions this season and 16 players with two or more forced fumbles this season. Of those 24 players that influenced two or more turnovers, 16, or nearly 67%, are defensive backs.
Looking at stats from the 2013...
Richard Sherman had 8 interceptions.
The leader in fumbles recovered was Mychal Kendricks with 4.
The leader in forced fumbles was Robert Mathis with 10.
It is tough to track because interceptions are a turnover, where forced fumbles may not be a turnover. I cannot find stats on individual turnovers created. There are team turnover differentials, but not stats for an individual (or position).
I would conclude that defensive backs, and more specifically corner backs create the most turnovers based on the stats available. Especially in today's NFL which is a passing league.
I do not have hard research to support this, however in my experience Quarterbacks have the most fumbles on any given team – generally speaking. Not the least factor in that is they touch the ball more than any other player.
Given that, I believe Defensive Ends are ”most likely to create turnovers in football”. [My college philosophy/logic professor is doing a facepalm.]
Probably by far and away; if someone were to ferret out the proper statistics. However – and of note – big cornerbacks (like the almighty Ronnie Lott) often have the most dramatic turnovers through interceptions and big hits across the middle; and those are the ones that imprint the largest in our minds – but I believe the numbers will flush out that the Defensive End is the correct answer [...unsung workhorse and most beautiful specimen of all Football players.]
(Note: It would be prudent to make sure the 2 corners and 2 safety positions are not combined into “backs” for comparison - as 4 players on a team just might collect more numbers than 2 defensive ends – and diggers3's excellently made point about forced fumbles not all being turnovers notwithstanding.)