It was announced on Friday afternoon that Barcelona had agreed a £96.8m deal with Borussia Dortmund for the transfer of the 20-year-old, who has become the second-most expensive footballer of all time.
The attacker scored 10 times and provided 18 assists in 47 appearances for Dortmund during the 2016-17 season, and Valverde has revealed that he cannot wait to have the Frenchman at his disposal.
"He is a player that guarantees us depth. Something we've lost and need," Valverde told reporters. "He can play on both sides and gives us many possibilities. Fast, deep, technical. Let's hope he brings us many things."
Valverde, meanwhile, also hinted that Barcelona's transfer business for this summer was not completed.
"We're going to wait. Until the market closes we have time," he added.
Barcelona will continue their 2017-18 La Liga campaign with a trip to Alaves on Saturday night.