How to see iv

Ya can't. The reason why you're able to see that in someone's photo is because they used a Unit Builder and hit the option to show IVs.

To find out a unit's IVs, you can look at a unit's level 1 stats or level 40 stats (I think there's a way to see it in between, but you need someone to provide the stats for it and even then can line up with another IV set) and compare what you see in game to what this site has on any specific character.