What MTD actually changes
Not the tax. The record keeping. Quarterly updates mean the year has to be recorded as it happens rather than assembled from a shoebox in January, and that is the part that catches people out.
Cumulative, not four separate returns
Each quarterly update restates the year to date rather than reporting three months in isolation. A correction to an earlier quarter is picked up in the next update rather than needing an amendment, which is a great deal more forgiving than people expect.
Who it applies to
It phases in by income level, and the threshold steps down over successive years. Combined property and self-employment income is what counts, not property alone, which is the detail that catches landlords with a side business.
What we do and do not do
We keep the figures from your records in the right shape, and send each quarterly update to HMRC when you press send, never on our own. The final declaration can be sent from here when UK property is the only income you need to add yourself. If you also have savings interest, dividends, self-employment or foreign property income, the page tells you to finalise that year with software that can add it. Anyone telling you their software removes your responsibility for the numbers is selling you something that does not exist.