What file formats does KDP accept?
Updated
For paperback interiors KDP recommends PDF (print-ready, fonts embedded); it also accepts Word documents but converts them with less predictable results. For ebooks KDP accepts EPUB and Word files, converting them to Kindle format on upload.
The safe combination for quality is a print-ready PDF for the paperback interior — pages exactly at your trim size, fonts embedded, gutter matched to page count — and a standard EPUB for the ebook.
Uploading a Word file directly hands layout decisions to KDP's converter: page breaks, hyphenation and spacing come out however the converter decides, which is the source of many 'my book looks different in the preview' surprises.
Always check the file in KDP's previewer before publishing, whatever you upload. A preflighted PDF exists precisely so the previewer confirms rather than surprises.