While liquidazione normally means transforming something into cash usually by selling it, in Italian VAT jargon it means filling out and filing the form (UNICO) to pay the VAT. As a result the form acts both as a tax return and a payment slip at the same time. For example if you are in credit for VAT, then you must still fill in and file the form showing the credit, otherwise you won't be able to deduct it or claim a refund in the future.
As my accountant recently said, "You have nothing to pay, but you must fill it in and send it in anyway."

What this line says is that (i) the form was filled in., (ii) it resulted in a debit balance and (iii) the payments made were equal to that balance.
Of course they could have said: "the firm paid its VAT", but that is in another culture.

I versamenti corrispondono al saldo a debito risultante dalla liquidazione perio