Once you are registered for MTD for VAT, you must NOT submit a VAT return using HMRC’s existing portal as it will not constitute a valid return.
Instead, ‘functional compatible software’ must be used to file the VAT return with HMRC. Most accounting packages will have this functionality built in. However if you use spreadsheets this will not be the case, and therefore you will need to purchase bridging software which will link your spreadsheet to HMRC’s systems and allow the VAT return to be filed. In these circumstances, the combination of the spreadsheet and the bridging software will constitute the ‘functional compatible software’.
Please note that the way VAT is calculated is NOT changing and so your VAT payments/refunds will continue to be worked out in the same way.