The verb IR is used with a (to) to say that you are going to a place.

• Voy al banco.  I am going to the bank. --- al - if going to a singular masculine place.

• Va a los bancos.  He/She goes to the banks.

• Vamos a la oficina.  We are going to the office. == a la if singular & feminine.

• Vamos a las oficinas.   We are going to the offices.