"Eu fac o cafea."

Translation: I make a coffee.

[Fredlag93]

The expression "I make some coffee" would be more common

[MarkFuller7]

This is another "Americanism".

[Lng52-._]

Or, "I make coffee".

[Renardo_11]

I assume the Romanian sentence (with "o") emphasizes that I make exactly one cup or portion of coffee.