What is how to respond to just an emoji?

As an AI language model, I don't have emotions, but I can guide you to answer that.

If someone sends you an emoji, here are some ways you can respond:

1. Respond with an emoji - You can respond with a similar emoji that conveys a similar emotion or sentiment. For example, If someone sends you a smiling emoji, you could respond with another smiling emoji.

2. Use words to acknowledge the emoji - You can use words to let the person know that you understand the emotion that they are trying to convey through the emoji. For example, if someone sends you a crying emoji, you could respond by saying, "I'm sorry to hear that."

3. Ask for clarification - If you're not sure what the emoji means or what message the person is trying to convey, you can ask for clarification. For example, you could respond with, "I'm not sure what you mean. Could you explain?"

4. Ignore it - If you're not interested in responding to the emoji, you can choose to ignore it. However, this may not be a good idea if the message is important.