Must Chile form f certificate of origin be issued before cus

It's the first time for our company to export form f certificate of origin to Chile. Today, we heard from the forwarder that form f must be issued before customs declaration. Do you need to fill in the certificate of origin number on the customs declaration form? Is this true? The customs declaration has been completed on March 27th, but the ship hasn't made it clear which day the ship will sail. Maybe tomorrow or the day after tomorrow, due to the need to show the sailing date on the form f certificate of origin, we haven't started to apply for the certificate of origin. So I want to know with you, do you really need to add the certificate of origin number on the customs declaration form? Where to add it? The sailing time hasn't been decided yet. Can the certificate of origin be issued?