Making pickled peppers generally requires boiling vinegar with sugar, salt and other ingredients and then pouring this hot liquid over the peppers. If using large peppers, they should be sliced into 1/4-inch rings, while smaller peppers can simply be pierced a few times with a skewer.
To make pickled jalapeños, combine 1 cup of apple cider vinegar, 1 cup of water, 2 tablespoons of honey or other sweetener and 1 teaspoon of salt in a small saucepan. Let this mixture come to a boil, and stir it until all of the sugar dissolves. While this mixture heats up, chop 1 bell pepper into small pieces, and crush 2 cloves of garlic, then add both of these to the sliced peppers. Put the pepper-and-garlic mixture into a large glass jar, and then pour the boiling liquid directly over the peppers. Let this mixture cool to room temperature, then put a lid on the jar, and store the pickled peppers in the refrigerator.
Bon Apetit's recipe for pickled peppers calls for 1 1/2 cups of distilled white vinegar, 3 cloves of garlic, 2 tablespoons of black peppercorns, 2 tablespoons of kosher salt and 2 tablespoons of coriander seeds. Add 2 tablespoons of sugar to this mixture, then heat to a boil, and pour over the peppers as in the previous recipe.