Green Peppers are the large, green sweet bell peppers that are very common in North American and UK cooking. If a recipe calls for Green Pepper, this is the Green Pepper it means — as opposed to say, Jalapenos.
Remove the seeds and discard them. They have no taste and will just get stuck in your teeth.
1 large bell pepper = 1 cup seeded and chopped
1 green pepper = 1/4 cup dried green pepper flakes (Source: So Easy to Preserve, 2014, page 364.)
5 tablespoons dehydrated green pepper powder = 40 g (1.4 oz)