Q.white spots on leaves of pepper and broccoli plants
What might cause these white spots on the broccoli and peppers? They are just getting out of the flats and have been in them for a while. What might we do to treat? Will getting them in the ground help them to recover?

Sounds like you picked up some diseased seedlings, or, if you grew them from seed, you had a fungus or bacteria in the soil that is now affecting your plants. Whichever it is (and there are several possibilities), you need to get control of it quickly before it spreads -- simply planting them won't get rid of it and in fact you may want to hold off planting them until you've treated them to avoid the disease spreading.
These articles may help you identify the issue and then treat appropriately:
https://www.gardeningknowhow.com/edible/vegetables/cabbage/cruciferous-leaf-spot.htm
https://www.gardeningknowhow.com/plant-problems/disease/white-rust-disease.htm
https://www.gardeningknowhow.com/edible/vegetables/pepper/bacterial-leaf-spot-on-peppers.htm
https://www.gardeningknowhow.com/edible/vegetables/pepper/common-pepper-plant-problems.htm