If you have already established and documented your tone of voice guidelines, you can simply incorporate them into a prompt whenever you want ChatGPT to create something for you, like this:
ChatGPT Marketing Prompt: "Please use these tone of voice guidelines when responding to my following prompt: It must be clear, easy to understand, and concise. It must sound authentic and human. It must inspire energy and provoke action. It must feel lively and energetic. It must sound knowledgeable and well-informed. It must be accessible and friendly, with no complex jargon."
An alternative approach is to simply show ChatGPT some examples of copy that matches your tone of voice, perhaps from existing resources such as blog posts or marketing materials. To do this, we must first explain to ChatGPT what we are trying to achieve:
ChatGPT Marketing Prompt: "I need you to help me create some text. First I want you to look at some examples of writing to understand the style you should emulate. After this prompt, I will paste a writing example for you to analyze, and I want you to say “OK”. I will keep posting new examples, and you should keep saying “OK” until I say “READY”. Then you should summarize the style and tone of voice in a few sentences before I ask you to start writing for me."
Once you have pasted in a few examples and then typed READY, the AI should tell you how it understands the tone of voice in the examples. You can then correct it with further instructions (e.g. “I want you to be less formal.”) before asking it to complete whatever writing task you need.