Sitting in water is the kiss of death for most plants. Is this potting soil you've used in your pots? And sure looks as if you haven't used any basic balanced fertilizer? NPK?
Are these plants on a window sill inside your home? Light from even a south window will not be enough to produce flowers and fruit and vigor. Do you have a covered porch? Putting them out of doors under a roof or awning that protects the plants from direct sun might make a difference. Don't move them from indoors to out of doors without complete protection from the sun at this point. Do you have an area as a garden? We can explain how to acclimate your peppers to the out of doors sunlight.
Get rid of all water in the bottom of that tray, lift the bottoms of the pots off the surface of those trays so water can drain out of your pots, use a basic fertilizer such as Osmocote 14-14-14 or Dr. Earth's All purpose 5-5-5.