ATHLIO1 or 3 Pack Men's Cool Dry Short Sleeve Compression Shirts, Sports Baselayer T-Shirts Tops, Athletic Workout Shirt

Q: The product title says there are 3 shirts we o my got 1 of the 3 why?

Hi there. The package is 3 T-shirts. Depending on which one you buy they may come all in the same color or different colors (Navy, black, etc.). Cheers

Q: Why do you change the sizes after the order is placed?

I think you mean 'how do you change the sizes after order'.it depends upon whether it's been shipped.Just make the changes in (your orders section on the Amazon site),or call them directly at the distributor /manufacturer in the 'contact seller's area.