This is one of the popular formations that people use in the game, particularly in Ultimate Team (FUT) as it crowds the middle of the pitch and also gives you two strikers for through-balls and a CAM that be used to play the through-balls and for shots around the edge of the penalty area.
A major downside to this formation is the lack of width as an opponent can double up against your full-backs if they make good use of possession and, as crosses are quite powerful in the latest version of the game, this can lead to goals being conceded.
However, with Dynamic Tactics, you can utilise this to counter an opponent that is making good use of the wings against your narrow formation by changing to a wider one or having a wider version of your 4-1-2-1-2.
The variation on the base version of this formation is the 4-1-2-1-2(2) which will mean that your LM becomes a CM and your RM becomes a CM. This makes the formation more compact and is probably more commonly used than the base version of this formation as a lot of people like the more narrow nature of this variation as timed finesse shots are so overpowered.
Ways to Score With This Formation
As this formation is one of the most narrow in the game it is not as likely that you will score with crosses from this one compared to wider ones such as the 4-3-3 or 4-4-2 so the best ways to score will be ones that happen down the middle of the pitch such as timed finesse shots and through-balls from the CAM to one of your two strikers who then finish a one-on-one with the keeper.
Ways That Opponents Will Counter This Formation
You will find that opponents may change to a formation that floods the middle of the pitch to combat you overnumbering them in there. Especially if you are using the Team Press tactic to put pressure on their team when in possession of the ball. They may use the 3-5-2 to add number to the middle of the park with an extra central defender against your two strikers and a CDM to mark your CAM and stop those through balls and timed finesse shots.