When CaCo3 is added to Hcl what is formed?

Calcium chloride, Water, and Carbon Dioxide.

Here is the BALANCED reaction equation.

CaCO3(s) + 2HCl(aq) = CaCl2(aq) + H2O(l) + CO2(g).

NB When writing chemical formulae, please use the correct symbols.

CaCo3 means one calcium atom and three(3) COBALT atoms. whereas I think you mean 'CaCO3' , which means 1 x (Ca)Calcium, 1 x (C)Carbon and 3 x (O)Oxygen.

Similarly, Hcl means nothing. , whereas it should be written as 1 x (H)Hydrogen and 1 x (Cl)Chlorine.

Note the use of CAPITAL letters for single letter elemental symbols and as the first letter for two letter elemental symbols. Please see the Periodic Table for the correct form of writing elemental symbols.