Mourinho made his comments after a brief appearance before a Spanish judge to answer questions regarding accusations of tax fraud.
The United boss is being accused by Spanish prosecutors of defrauding the country's tax authorities of €3.3m ($3.8m) in unpaid taxes in 2011 and 2012.
"I was informed that an investigation was opened and they told me that in order to regularise my situation I had to pay a certain amount of money," Mourinho said as he left a courthouse on the outskirts of Madrid. "I did not complain (or) appeal and I paid and I signed an agreement and a compliance act with the state, saying that everything was closed. For this reason I was here only for five minutes to say the same things I am telling you."
The money in question involves revenues from image rights, not salary paid by Real Madrid.
The 54-year-old Portuguese coach was in charge of Real Madrid from 2010-2013.
After the tax fraud accusations were announced in June, the agency that represents Mourinho, Gestifute, released a statement saying that the coach paid "more than €26m ($30.3m) in taxes, with an average tax rate over 41 percent, and accepted the regularisation proposals made by the Spanish tax authorities in 2015 regarding the years of 2011 and 2012 and entered into a settlement agreement regarding 2013."
The agency said tax authorities issued a certificate in which it attested that Mourinho was in compliance with all of his tax obligations. It published copies of the certificates.
Mourinho is the latest football figure to be targeted by tax authorities in Spain. Last year, Lionel Messi and his father were found guilty on three counts of defrauding tax authorities of €4.1m ($4.7m) from income made from image rights.
Cristiano Ronaldo, Marcelo, Ricardo Carvalho, Angel Di Maria, Javier Mascherano, Radamel Falcao and Fabio Coentrao are among other players investigated by Spanish tax authorities.