You need to provide more information on your growing conditions: location, weather, watering method, etc. More pics would help, especially if they show these spots in the early stages of forming.

Looks like sunscald to me. I'd put them in the shade for a day and then slowly introduce them to the bright sunshine.

Linda

That looks like young tomato foliage. Transplanted out too early without hardening off, as Linda said above....sun plus possibly endured some cooler than 68F overnight temperatures too fast equals sun scald. Abuse at the BigBox nursery section is also very likely (uneven watering and overnight cold stress). This damage will DELAY growth, but it isn't fatal. But in future, never plant (or buy plants left outside at the BigBox store) tomato and pepper plants that are too early set outside to endure cold nights. Instead of "getting ahead", as the retailers all try to outdo one another, overnight temps below about 68F will only set you back. Remember to always plant your tomatoes in a deep trench up to their first few sets of leaves to ensure they get all that hairy stem actively growing roots to recover and hold your fruit against droughty weather later in the season. This will also help that stress if you find your newly planted tomato bronzing off this way--rip it out and bury it super deep. It will seem pitiful, but it will reward you later.