You can determine by their numbers written on them or on their boxes. 2700K, 3000K for flowering. Can be written as 827 or 830 or some other ways depends on manufacturer. Over that you can use for veg. 6500K is ideal for that.
You can also determine by their colors. Orange, yellow or pink are good for flowering. White, blue white is good for vegging. Green white is like neutral but can be used for vegging as well if there is no other options. I prefer using orange ones instead.