You normally need to register as an employer with HM Revenue and Customs (HMRC) when you start employing staff, or using subcontractors for construction work.
You must register even if you’re only employing yourself, for example as the only director of a limited company.
You must register before the first payday. It can take up to 5 working days to get your employer PAYE reference number. You cannot register more than 2 months before you start paying people.
If your business starts employing people on or after 6 April, you’ll get your employer PAYE reference number by 31 July.
To pay an employee before you get your employer PAYE reference number, you should:
Run payroll.
Store your full payment submission.
Send a late full payment submission to HMRC.
If you don't yet have your PAYE reference number and want to run a pay run. Please get in touch with a member of the support team.
Source: gov.uk