Is hcl a compound or element?

What is 'hcl'???? If you mean 'HCl'. then it is a compound of hydrogen combined to chlorine.

To for form hydrogen chloride gas , or dissolved in weater to form hydrochloric acid.

NB When writing chemical formula, single letter element are ALWAYS a CAPITAL letter , Hence hydrogen is 'H' not 'h' and similarly a two letter symbol ; first letter is a CAPITAL letter and the second letter is small /lower case. hence chlorine is 'Cl'. not 'cl'.

This is the recognised IUPAC international standard and is shown in the Periodic Table.