The teenage attacker has scored 26 goals in all competitions this season, helping the principality club to the Champions League semi-finals and break Paris Saint-Germain's dominance of French football.
Manchester rivals City and United and Spanish champions-elect Real Madrid have been strongly linked with close-season moves for Mbappe that could see sums tipping nine figures.
Carvalho was a substitute alongside Mbappe before he emerged from the bench to make his debut against Tottenham in the 2015-16 Europa League and, having won the Premier League with Chelsea before playing in Spain with Real Madrid, the Portuguese has backed the 18-year-old to make an impact wherever he goes.
"He already showed that he was a different player... that he had quality, talent, although we already know the talent that he has," Carvalho told Omnisport.
"But the truth is that in order to grow it is important to play and this year the club allowed him to play more often. Football is like this, playing, making goals and gaining confidence makes the player grow even more.
"And fortunately for him this year was an important year because it was the year of his confirmation as a top player."
Asked where Mbappe could take his talents next, Carvalho replied: "I do not know, but it's important to let him continue to grow. I think he has ambition to play in a big club, but sometimes, like everything in life, what seems to be the best option may not be.
"Who am I to say if LaLiga or the Premier League is better? I think he has characteristics that he can get along in both. Because he is speedy and attacks the spaces well.
"He is a player who can make a difference in both the Spanish league and the English league."