i am purchasing a mens backpack from ua soon. Doulingo helped me buy it completly in itailian.
It really was a thrilling expirence.
Try a few little corrections: "I am purchasing a man's backpack from you soon. Duolingo helped me to buy it completely in Italian".
These aren't really corrections. For example, "helped me buy it" isn't incorrect.
And is sounds a good bit better than the proposed alternative in my estimation. And "man's backpack" probably isn't what the OP meant.
Now why one would need to use Italian to use the Under Armour website, that is a separate question. Seems a cool adventure though :)