When I opened the document to edit it in Word Online, I received a notice: "ODT Document Some compatibility issues could occur if you edit this file," followed by a link to details.

Versions of the software from Word 2013 forward, including Word 2016, Word 2019 and Word for Office 365, all have the capability to incorporate PDF files directly into a Word document.

8. ODT files are part of the Open Document Format (ODF) files, which are XML-based, Open Source file formats. . ODT files are for word processing programs.

The Office programs even offer to convert the files immediately via “Download as PDF” and “Download as ODT” (Word), “Download as ODS” (Excel), or “Download as ODP” (PowerPoint).