Is the cover letter only to be used with a paper resume? No. If you are sending your resume via e-mail as an attachment, the accompanying e-mail is your cover letter. And if you are submitting your resume directly to an online database, you will often have the opportunity to include additional attachments, such as your cover letter. The resume explains your features, your cover letter explains your benefits. Do not pass up this opportunity to fully communicate your value, whether on paper or online.