We do require a CV (resume) in PDF format. Otherwise, your profile will not be attractive to companies.
The better your CV, the more it shows how serious you take your job search. There are multiple services online to help you build a strong CV. One good tool is Standard Resume, for example, and there are others as well.
If you want to use the LinkedIn feature to save your LinkedIn profile as a PDF, be sure to double-check that the PDF does not have any typography errors. The PDF conversion does not always work properly.