It was developed to help emergency services and humanitarian organizations to get locations from people in the field during disasters and emergencies, but it can be used for anything else.
The common approach to use it is:
1. Create a WhatsApp group and invite people to it
2. Ask people to share locations followed by a message or a picture
3. Export the chat (with or without media) to a zip file
4. Upload the file to chatmap.hotosm.org