A new supplier is requested a VAT number as part of their sign up process but I do not have one. How to proceed?
If you are not yet VAT registered and therefore do not yet have a VAT number, you should just explain this to your supplier.
As you are a new business, they will understand that you are a not yet VAT registered and should not require a VAT number.
If it is a new account application form that you are filling in, you can just enter 'N/A. Not yet VAT registered'.