A covalent bond is formed between H and Br
The structure of HBr is as follows
H —Br
Formal charge for atoms are the charges for individual atoms in compounds.
Formal charge can be calculated as follows ;
Formal charge of atom = number of valence electrons -( number of bonds + number of lone pair electrons)
H has 1 valence electron, 1 bond and 0 number of lone pair electrons
Formal charge of H = 1 -1 -0 = 0
H has 0 charge