What is the correct file format for your resume? There is no one answer. There are actually two or three, or four if you really want to go the extra mile.
The industry standard for documents is Word. Why? Because of the market penetration of Word in the business world. So your baseline resume should be done in Word. Which version? Although there are some forward compatibility problems with old versions of Word, save your documents in the current format of your copy of Word. And make sure you use Word to save the document, not some other program saving in Word format (since it does NOT always translate correctly, especially with bulleting and formatting). If you don't have a copy of Word, use it at the computer center, career center, library, or on someone's machine with a registered copy. This Word document is your baseline resume document which you should use for all updates and revisions. For free resume templates in Word of the best format to follow for your entry level resume, see the Quickstart Resume templates at CollegeGrad.com: CollegeGrad.com/resumes.
Most word processing programs give you the option to save or export your document as a PDF. The Portable Document Format maintains all of your content and formatting in a universally compatible file that will look nearly identical on any device or operating system. This is a great option if you don't have access to Microsoft Office since there are many free Office alternatives that include PDF exporting. It's important to understand that this type of file is not a "working format" that you edit and revise, it's simply a snapshot of the current state of your document. You should create and maintain your resume in Word and then export to a PDF only when you have a final, customized version to give to an employer. PDF is a suitable substitute for Word format in most situations, unless the employer states otherwise.
After you have developed your resume in Word, do a "Save As…" in "Text Only with Line Breaks" format (or "Text Only" if that is the only text option available). The reason for saving it with the line breaks is that it will automatically put hard carriage returns in at no more than eighty characters per line. There are two advantages and one disadvantage in doing this. The advantages are that it will keep your resume from running off the right side of the screen when being viewed without word wrap and it will avoid any truncation of information (often after 1,000 characters in a paragraph—uncommon, but it does happen with some systems). The disadvantage is that some systems automatically word wrap at under eighty characters (seventy-two is the most common), so the hard carriage returns can often leave one or two words on a single line. But the advantage (being able to read the entire resume) outweighs the disadvantage (formatting imperfectly), since this resume will be used primarily for input into resume databases and applicant tracking systems (ATS). After you have done your "Save As…" you will still need to modify the resume in text format. Use a text editor (such as Notepad) to view the resume. Most notably, any indents will move text over eight characters instead of the predefined indent you may have set for Word. Also proofread for any unusual characters or symbols which may not have converted properly. Lastly, left justify everything to the left side of the document. It doesn't have to be pretty, just readable.
If you want to take your resume one step further by posting it on the Web (NOT for resume database posting, but placing on a Web page of your own), you can do a "Save As…" with "Web Page" selected. Again, the formatting will not necessarily translate exactly from Word to the Web, so you may have to change some of the HTML to properly format (or at least end up with a close fit). This format is optional and only needed if you plan to place it on the Web directly (more on the reason for doing this). A more convenient way to create and share your resume on the web is with CollegeGrad's Quickstart Resume Generator. Just fill in the resume content and we'll build a great-looking web resume and give you a shareable link.
So when and where do you use these three different versions? The Word and PDF versions are used for printing, for sending as an attachment (unless text is requested specifically), and for uploading as an attached document for job applications on job sites such as CollegeGrad.com. The text version is typically used for Internet resume databases and for any online submission which would find its way into an employers ATS. And the HTML version is only used for posting to your own Web page.