The deal is reportedly worth up to €67million (£56.57m). Raphinha's move is subject to a medical being completed.
Chelsea and Arsenal were both heavily linked with the former Sporting CP attacker, with the Blues striking a deal with Leeds in late June to bring the winger to Stamford Bridge.
However, reports suggested that Raphinha was prioritising a move to Barca, with Blaugrana president Joan Laporta announcing "he wants to come".
Xavi's side is contending with well-documented financial issues, with Laporta revealing new signings Franck Kessie and Andreas Christensen could only be registered after salary adjustments.
But Barca has seemingly made further alterations to secure the services of Raphinha, who is set to sign a five-year deal.
Raphinha scored 11 times in the Premier League for Leeds in his last season, after netting six goals in the 2020-2021 season after his arrival from Rennes.
That marked his best return in front of goal since he struck 15 times in the 2017-2018 campaign Portuguese side Vitoria Guimaraes.
Indeed, since making his Leeds debut, he has directly contributed to 29 Premier League goals, scoring 17 times and managing 12 assists, at least five more than any team-mates in the period.
Xavi will hope Raphinha can continue his scoring form when Barca opens their LaLiga campaign at home to Rayo Vallecano on 13 August.