When writing the name of ionic salts, you need to write the name of the cation, followed by the name of the anion.
In your case, the formula is Ag2CO3.
This means that
- the cation is Ag+ (you have two of them). The name of that cation is silver ion. Silver is an an invariant cation, so you do not need to indicate its charge (+1) as a roman numeral (I).
- the anion is CO32–, which is the carbonate anion.
So the name of the compound is simply silver carbonate.