The intention is for the whole process from capturing the data in your bookkeeping software through to submission of the final results to be digital with very little human intervention.
At the moment, you could keep a carrier bag of paperwork and then summarise all this on the back of a couple of envelopes, add up the totals and then input those summarised results onto HMRC's website. HMRC don't like that as they think it's prone to errors. The reality is that if you've just got 12 sales invoices and a handful of expenses you're just as likely to end up with the right result as if you had software you paid £50 a month for.
However, if you've raised hundreds sales invoices in the year and have hundreds of expense invoices and you're VAT registered, you're probably best using software to keep track of it all properly.
The idea is to capture the data as soon as it's created so;
- you'd create your sales invoices in the MTD compliant software. Or in the case of retail sales, you'd link your till system to the MTD compliant software so it automatically transfers the figures
- you'd link your bank account to the MTD compliant software so it automatically imported each transaction
- you'd match the sales invoices to the transactions imported from your bank account
- you'd match your expense receipts to the transactions imported from your bank account
The software does all the adding up and there's no need to transfer any numbers manually from a piece of paper or another software package into the data which forms the submission to HMRC. As HMRC see it, this minimises the risk of errors. However, it doesn't deal with errors where a trader accidentally analyses something incorrectly or includes something which isn't a business expense or treats income as not taxable. It also doesn't take into account that the software and electronic links to other data sources can fail. For instance, the process of obtaining the bank transactions, known as a bank feed, can fail to import some transactions or report some transactions twice. It would be up to the trader to be vigilant enough to review this and correct the mistakes.
In theory it could work perfectly but in practice there's always a few problems.
I would say that some of the software out there does a very good job and as an accountant I've found Xero to be my preferred software. It works well, has good online support, is well featured and does save me time dealing with clients' bookkeeping. My clients seem to like it too. However, at its cheapest, it's £14 plus VAT per month to non-accountants.
I have also used FreeAgent. It's not as good but for those who have their primary bank account with NatWest, RBS, Ulster Bank or Mettle it is free! For everyone else the cheapest version for non-accountants is £19 plus VAT per month. If you have to pay that then I'd choose Xero.
Both Xero and FreeAgent are cloud-based solutions.
In the past I have experience of using Quickbooks desktop software. But, in my opinion, it's too easy to make mistakes. At least, that's what I've found reviewing the data from clients who've used Quickbooks. Their online product Quickbooks Self-Employed is just crap so avoid it. Their more feature-rich online products maybe better but I haven't tried them and are more expensive.
I've not taken part in HMRC's pilot scheme for MTD for Income Tax so don't have any experience of using the software for that but all three of them claim to be MTD for Income Tax compliant.
There are plenty of other software providers which are supposedly MTD for Income Tax compliant including Sage but I haven't had time to try them out so can't comment.
Having said all that, the deadline for needing to be MTD for Income Tax compliant is still some time away and there's plenty of time for other software suppliers to produce useful and cheaper alternatives.
ETA: with most of the software available you can try it out for free for a while so I'd suggest trying out two or three packages to see which one suits you. For instance, one client chose Quickbooks SE as it had a built in car mileage calculator and that was important to them.