Rashford will join the Barcelona squad on loan. Therefore, everything will depend on his performances. I believe Rashford will find success in Spain with his style of play, just like Antony. Antony had a great time at Betis. Rashford will surely do the same.
If he is given the opportunity to play more, I'm sure he will give his best for Barcelona, but the question is whether Hansi Flick will give Rashford a starting spot because, as far as I know, Barcelona's front line is already filled with Lamine Yamal, Rapinha, and Lewandowski. But I think Rashford is only used as a rotation option when Barcelona faces average clubs in the La Liga competition later. Well, when Rashford is given such an opportunity, it should be an opportunity for him to show his best so that management is interested in making him permanent.