What are these bugs and spots on my Chilli Plant

Before you do anything else, quarantine this plant. You don't want other plants to be infected.

These bugs are most likely aphids, probably black bean aphids. The shiny stuff on the leaves is honeydew produced by them. These bugs are bad news for your plant. They suck sap from the plant, reproduce quickly and will take over your plant. without treatment the plant will probably die. The honeydew is a problem because mold can form on it and your plant can rot away.

So how to get rid of them? You have a few options:

1. Manual remove them. Rinse the plant with water and try to wash them away. Place the plant in the shower or use a garden hose. Inspect the plant afterwards and manually squeeze any bugs that stayed behind.

2. Get natural enemies to eat the bugs. In nature, larger insects (for example ladybugs, lacewings and soldier beetles) love eating aphids. I don't know which ones work best in India. You can buy these insects at some pet stores or in some specialized webshops. The benefit of positive bugs is that they find the aphids for you. Drawback is that they might fly away before finishing their job. Also, bugs are often expensive.

3. Use a chemical detergent. You can find these products in any gardening store. Not all generic bug-sprays have effect on aphids so make sure the product you select works effectively against aphids. Since you are growing plants to eat, take extra care in selecting a product that is not harmful to people. When applying, make sure the substance touches all aphids. Only when an aphid touches the substance it dies.

Getting rid of such an aphid infection takes a long time. After removing them once you will have to check the plant regularly to ensure they don't come back.