Start with the material you have. An empty page calls for drafting; an existing paragraph calls for editing. Compare tools using the same passage, audience and tone, then check that the revision preserves your meaning.
For a first draft, give ChatGPT or Claude a brief with the audience, length and required facts. For a rewrite, try a short passage in QuillBot and check whether the result keeps the original meaning.
Scroll the table sideways for all limits and official sources.