A PDF describes where marks appear on a page. A Word document describes a flow of paragraphs. Converting between the two means reconstructing information that was thrown away when the PDF was made, which is why every converter — including ours — produces an approximation rather than the original source file.
These guides set realistic expectations for each direction of conversion, explain why formatting drifts, and describe when a rasterised image is the better answer than an editable document.
A PDF stores positioned glyphs, not paragraphs — so conversion has to infer structure that was discarded when the PDF was made, and inference is imperfect.
JPG for pages that are mostly photographs, PNG for pages that are mostly text and line art — and set the resolution from where the image will be used.
Each image becomes one page, so the decisions that matter are page size, orientation and how much resolution you keep.