what are journaling prompts?

Journaling prompts are ideas that help you better focus your attention on what to write, while also giving you some guideline and inspiration. Common prompts for journaling are usually in the form of questions, such as:

What am I feeling today?
How do I want to feel instead?

Other prompts that are not in the form of questions could be:
List three things you appreciate about yourself.
Reflect on a moment of abundance in your life.

There are hundreds of prompts, you can also make up your own. There isn't any rule or specific prompts that should be used, they are just meant to help guide you and give you better focus on what to write.