Many employers use applicant tracking software to store and search resumes. A clean, simple file is read correctly. A fancy one can come out jumbled.
An applicant tracking system (ATS) collects applications, turns your document into text and lets a recruiter search it. A person usually makes the decisions. The software mainly stores and sorts. If it cannot read your file, your details may be mixed up or missing.
Read the job advert and note the skills and tools it names. Where you really have them, use the same wording in your experience and skills sections. For example, if the advert says "customer service" and you write "client support", add the advert's phrase too. Do not paste in skills you do not have, because interviewers will ask about them.
Copy all the text from your PDF and paste it into a plain text editor. If the order is sensible and nothing is missing, most software will read it well. Resumes made with Resume Desk use plain, selectable text.