Mourinho has previously played down charges and insisted that he left Spain with the "information and conviction his tax situation was perfectly legal".
José Mourinho has accepted a one-year prison sentence on top of a €2m fine for tax fraud as part of a settlement with the Spanish authorities.
He had previously paid a fine of 1.14 million euros in 2015 for an administrative offense related to the same case.
Mourinho has been out of work since he was removed from his role at United in December after two-and-a-half years at the helm.
The Portuguese tactician was accused of owing Spanish tax authorities approximately €3.3 million (R50m) in unpaid tax.
India's Predicted Playing XI for 1st T20I against New Zealand
As far as the match is concerned, India won it by 35 runs, with Ambati Rayudu and Yuzvendra Chahal playing an important role. Although they pulled one back, skipper Kane Williamson will be disappointed with his side's performance in the ODI series .
According to the agreement seen by AFP, The Special One accepted a one-year jail sentence, which was immediately commuted to a fine of 182,500 euros (208,461 US dollars).
Mourinho is the latest high-profile personality to have reached a plea bargain deal with Spanish authorities.
Mourinho has been linked with a return to Real Madrid after reportedly turning down the Benfica job.
A number of prominent figures in football, including former Madrid striker Cristiano Ronaldo, his ex-team-mate Marcelo and Barcelona forward Lionel Messi, have been punished for tax offences in the last two years.
Prosecutors said he had created offshore companies to manage his image rights and hide the earnings from tax officials.