HMRC published a new notice (700/22) in July with more detail on Making Tax Digital for VAT (MTDfV).
The notice confirms that MTDfV will apply to all businesses for the first VAT period starting on or after 1 April 2019 where their turnover was in excess of the registration limit (currently £85,000) in the previous twelve months.
If your business is VAT registered but has a turnover below the registration limit, you don;t need to follow the MTDfV rules, yet.
For more information – https://www.gov.uk/government/publications/vat-notice-70022-making-tax-digital-for-vat/vat-notice-70022-making-tax-digital-for-vat