After winning San Remo, Angelina Mango confirmed that she will represent Italy in the Eurovision Song Contest. She did that in the winners press conference after the contest.
It is the procedure: the winner of the Festival di Sanremo gets the first choice to represent Italy. He or she can however chose not to. This is the rule since 2015. Only in 2016, when Stadio won Sanremo, they chose not to go to Eurovision. Francesca Michielin, who reached a 2nd place, went to the contest in Stockholm instead.
Angelina Mango will (likely) sing “La noia”, a song she co-wrote with Dario Faini and Francesca Calearo.