If your VATable turnover is more than £85,000 in a 12 month rolling period you will need to register for VAT https://www.gov.uk/vat-registration Most landlords letting domestic property are exempt.
If the existing business is VAT-registered, the VAT registration can be transferred to the new company so that the existing VAT number is retained. This can be done online via the trader’s VAT online account or by post on form VAT68. HMRC will normally transfer the VAT number within three weeks. The threshold for VAT registration is £85,000. Where all or most of your customers are VAT registered consider voluntary registration as your customers can reclaim the VAT you charge and you can reclaim the VAT on your expenses.
If you are not already using bookkeeping software now is a good time to update your bookkeeping system. We can train you up on QBO or VT or do the bookkeeping here for you.
Consider using “cash basis”. Also, have a look at the Flat Rate Scheme which may allow you to save some money on charging VAT.