When creating an Apple Developer Account, if you have chosen the Entity type Company / Organization, you will be asked for a DUNS number in the next step.
So what is this D-U-N-S number?
"D‑U‑N‑S" (which stands for Data Universal Numbering System), is a system used to maintain up-to-date and timely information on more than 280 million global businesses. It is a proprietary system developed and regulated by Dun & Bradstreet (D&B). It assigns a unique numeric identifier - referred to as a DUNS number - to a single business entity.
Why do I need it to create an Apple Developer Account?
Apple has a policy where they verify every single company before letting them create a developer account. To make the verification easier and faster, Apple requests all businesses to enter their DUNS number.
Note: Currently, this method of obtaining a DUNS number is absolutely FREE.
If you don't have a DUNS number, or if you're not sure whether you have one or not, or if you have one and have forgotten your DUNS number, you can follow these steps to reyour DUNS number.
Step 1: Visit this link: https://developer.apple.com/enroll/duns-lookup/#/search. In case you're asked to log in with your Apple ID, please do so.
Step 2: Enter your Company information. Country, Name & Address.
Step 3: Enter your contact details and then press continue. Note that your DUNS number will be sent to the e-mail ID you have provided. Enter it here.
Step 4: You'll be asked to verify your details. Ensure all your details are correct. Once it is done, you can agree to the Terms & Conditions, and then click the Submit button.
Step 5: Now you'll be shown the status page. Usually, you will receive a confirmation mail from the D&B team shortly after you fill the form. You will receive your DUNS number 2-3 business days after this.
The process may get delayed by a few days if the D&B team requires additional information from you to verify your registered business. Sometimes this depends on the country of your business.
Once you receive your DUNS number from D&B, you can proceed with creating your developer account by following this link: https://developer.apple.com/enroll/.
Follow this link for a step-by-step guide on creating an Apple Developer Account: http://docs.vajro.com/creating-developer-accounts/how-to-create-an-apple-developer-account-a-step-by-step-guide.