Why recruiters ask for a PDF, not a Word file
A .docx resume renders differently depending on which fonts are installed on the reader's machine and which version of Word (or Google Docs, or LibreOffice) opens it — a carefully tuned one-page resume can silently spill onto a second page. A PDF locks in exact positioning, fonts, and spacing regardless of what the recruiter opens it with.
Converting your CV to PDF right before sending it, rather than keeping it as your working format, means you get to edit in whatever tool you're comfortable with and only "freeze" the layout at the last step — done locally here with no upload of what is, after all, a document full of personal information.