That would ideally depend on the client's requirement set.
Creative liberty in copywriting is almost always a discretional matter and is largely influenced by the desired output.
For instance, if you've been contracted to write a blog - depending on how the client wishes to pursue traffic - he/she may either ask you to adopt a specific tone (Viral, infomercial, pure informational, technical, semi-technical etc.) or straight up provide you with a list of keywords (and secondary or tertiary keywords) and instruct you on the usage.
If you've been asked to write a very specific guide, a how-to or an FAQ section of the article, generally keywords are secondary and valuable information is considered more imperative in such cases. At such times, the clients may only provide you with the topic - for instance, "How to setup an Ubuntu Server on Vultr?" and let you fly with it.
If the requirement is on a sales front viz. Sales letters, Amazon Reviews, CB Reviews etc. - then the client would generally want a specific structure followed. For instance,
- Introduction
- Who needs the Product
- How to use the Product
- Pros
- Cons
- Similar Products
- Conclusion
(The above is a fairly rough outline and can change depending on what the client wants.)
If you're doing SEO content, then keywords take precedence over everything else. In scenarios, where keywords are primary, the actual topic of the content is dependent on how the site is laid out.
For instance, in sites where the primary intent is to merely get a reader on the page and then grab their attention through pop-ups, lead generation forms or Pay-per-call numbers - the client should ideally let you write about almost anything, as long as the keyword is included. Whereas, in instances, where the ranked content is in itself a call-to-action - the client should provide you with a more detailed breakdown on what is needed or expects you to understand what the site/page requires for that particular keyword.
