Registering for VAT depends on how much money your business makes each year, rather than the legal structure of your business. The business structure does inform how you register for VAT, though. Sole traders register in their name, whereas limited companies register for VAT in the name of the company, and not the owner.
What is the VAT registration threshold?
The VAT registration threshold is £85,000 in any 12 month period. If you reach the end of a month, and your annual turnover from the previous 12 months is more than £85,000, you'll need to register!