You should get yourself FIFA or Football Manager & have a mess around for yourself. Formations play a big part in how your team will set up & play, weather you want to play wide or narrow, weather your defence to be deep or play a high line, weather you want one striker or two. And even though you maybe be playing the same formation as another team you can still have different stlyes, maybe both teams are playing 4-3-3, but one team might be using a target man to play long balls into & the other might try to keep the ball down & pass into space. There are so many combinations of styles and tactics which is what is so beautiful about our game. also maybe have a read of a couple articles in r/footballtactics, that might give you a little more of an insight into how tactics change games.