Since the early days of establishing itself as it's own country, America has always been a powerhouse within the world theater. Because of this, they have always been featured in Civilization games, even though they are a fairly new civilization as far as this game goes.
America's Leader
To change things up this time around, we've got Theodore "Teddy" Roosevelt leading the American people instead of George Washington. Teddy brings the leader bonus 'Roosevelt Corollary' to the game, which will give all of America's units a +5 to combat strength when they are fighting in their own continent. As if that bonus wasn't enough, you'll also get a +1 appeal to all tiles within a city if there is a national park present. Teddy also brings his own unique unit, meaning that America has two different unique units. More on that later.
Special Ability
While playing as America, you'll have access to the 'Founding Fathers' unique ability that will allow you to gain legacy bonuses for government types twice as fast as any other civilization. This can equal out to some pretty huge advantages pretty quickly that other civilizations won't be getting for a while, and should give you an edge over your rivals even in the early game if used correctly.
Special Building
Instead of the broadcast tower, America gets access to the Film Studio building instead. This can be built inside of a theater district. This building will give an extra 100% tourism pressure from this city towards other civilizations, which can easily set up America to win via a cultural victory if you put in enough of these in with some attractions to bring in tourists.
Special Units
America gets two different unique units, the b-51 Mustang, and the Rough Riders. The 51-Mustand replaces the normal fighter plane unit, and gains +5 attack against fighter aircraft, has +2 flight range, and gains +50% experience. With the rough rider unit, Culture is earned from kills on their Capital's continent. They also gains +10 Combat Strength when fighting on Hills. Of the two, the rough riders would be much more useful, as that added culture with each victory can help a great deal towards earning a cultural victory.
All in all, America is a very strong military power, but with the added strength of a strong culture. This should give you a few options on how to achieve victory in your Civilization 6 game while playing as the Americans.
America's Leader
To change things up this time around, we've got Theodore "Teddy" Roosevelt leading the American people instead of George Washington. Teddy brings the leader bonus 'Roosevelt Corollary' to the game, which will give all of America's units a +5 to combat strength when they are fighting in their own continent. As if that bonus wasn't enough, you'll also get a +1 appeal to all tiles within a city if there is a national park present. Teddy also brings his own unique unit, meaning that America has two different unique units. More on that later.
Special Ability
While playing as America, you'll have access to the 'Founding Fathers' unique ability that will allow you to gain legacy bonuses for government types twice as fast as any other civilization. This can equal out to some pretty huge advantages pretty quickly that other civilizations won't be getting for a while, and should give you an edge over your rivals even in the early game if used correctly.
Special Building
Instead of the broadcast tower, America gets access to the Film Studio building instead. This can be built inside of a theater district. This building will give an extra 100% tourism pressure from this city towards other civilizations, which can easily set up America to win via a cultural victory if you put in enough of these in with some attractions to bring in tourists.
Special Units
America gets two different unique units, the b-51 Mustang, and the Rough Riders. The 51-Mustand replaces the normal fighter plane unit, and gains +5 attack against fighter aircraft, has +2 flight range, and gains +50% experience. With the rough rider unit, Culture is earned from kills on their Capital's continent. They also gains +10 Combat Strength when fighting on Hills. Of the two, the rough riders would be much more useful, as that added culture with each victory can help a great deal towards earning a cultural victory.
All in all, America is a very strong military power, but with the added strength of a strong culture. This should give you a few options on how to achieve victory in your Civilization 6 game while playing as the Americans.