What is the best formation to win a game a 442 or a 343 formation at soccer

depends on the opposition but ill answer as an England manager they never do anything other than 442

4-4-2 ......any one tried .....5-3-2...yes sir, 5 3 2
Vital with this formation is 3
5 + 3......when attacking.. time of possesion and.." probability of score " markedly higher.....2 + 4
2 + 3.....defending against ...the 4 forward players ...is still an edge and as you get the ball ..a long pass to your forward line of 5 ...against 2 ..?.
You get the picture .......
See the 442 is a classic but if the team wants to focus on the attack and score as many goals as possible, 343 is better. But of course they need to have 3 strong defenders to keep the balance. So very few teams are able to pull it off. Manchester United is probably the team that used it most last season and they had the biggest goal tally.
4-4-2 keeps it more balanced I'd say 3-4-3 is too dangerous