Answered by Steve, Hiring Expert at Caterpillar Inc., on Friday, May 22, 2015
This is a good tactical question. Definitely attach the resume in a separate Word or PDF file. As for the cover letter, it should be separate, but many company careers sites give you a space where you can free form type in a cover letter. If this is offered, I would take advantage of this. Don't stress too much about the cover letter, though. Customize each cover letter for the job to which you are applying, but it does not have to be lengthy. Simply state your strong interest in the company and the position and express that you look forward to the next steps in the process and learning about their organization. This should be all you need to include. If they simply want you to send an e-mail for your application, I would use the body of the e-mail for your cover letter and attach the resume in a separate file.