Always use an appropriate template for documents that you write at work.
If they're good templates and you use them well, you are more than half-way to achieving an accessible document.
It's easy to pooh-pooh MS Word as a tool. It's so familiar. You have been using it for years. In your heart of hearts, you may feel you know pretty much everything you need to know, and that you have the right to design your own documents for work.
But you pay a price for bypassing the company templates. Read on...
A properly constructed template produces many benefits
Besides documents with an easily recognized brand, see what you gain with a template:
What if you don't have a template?
Ask your communications team for an appropriate template. This template is not just for you: all staff should use it. If you don't have a suitable template, someone needs to create one from scratch.
Your DOC gains many accessibility features from a good template. And when you convert your DOC into a tagged PDF, those features will be retained and reflected in the PDF. Brilliant!
What if the template has problems?
Don't try and fix your document by fiddling with Styles and layout: that won't improve accessibility—in fact, it may make matters worse. Instead, contact the template designer or owner, or your communications team. If you have template problems, so do other staff writers, and the problems need to be fixed at the source.
For accessible documents, don't take short-cuts