Yes you can add some cream to your Americano espresso if you want too and it will make the Americano espresso taste better than it normally would without it.
I can't drink an Americano without adding some creamer or Half and Half to the Americano as it's just a bit too strong tasting to me without the creamer.
You can add regular cream or regular coffee creamer or any type of milk etc to the Americano if you want too.
Some people can take the Americano without the cream but some people like me need the cream to be able to drink it.