FDA registration number is one of the primary requirements for the manufacturers to sell their products in the USA. Although FDA certification is a must for drugs and medical devices, the FDA registration number is not mandatory. It is a unique registration number that describes that the establishment is registered with the US FDA. It does not prove that the establishment or product got approval by the FDA. This number is for the manufacturers not for the specific products. So, you can’t label the FDA registration number on your products. Visit FDA Registration body in UK