Prompt (aka system message) contains custom instructions for the model and is included at the beginning of each conversation. Use it to set the tone, context, or role of the conversation.
Use the prompt library to save and manage your prompts. Use the default prompt dropdown to assign a default prompt for each provider. All new conversations will start with the default prompt.
Prompts are synced with iCloud and are available across all devices.
... menu button in the chat toolbar and opening Chat settings.