Many applications in Windows and Mac OS support printing to PDF, rather than a printer. Printing to PDF will covert your existing file to a .pdf file type. This allows you to convert images, documents and many other forms of text/image file to the .pdf format. Exact steps will vary between programs, but some common ones are outlined below.

Windows

Open the file you would like to print to PDF.

From the top menu bar, select File, then Print.

Under Print, select Microsoft Print to PDF.  Then, select Print.

Enter a File Name and select a location on the computer to which the PDF will be saved.

Click Save.

Mac

Open the file you would like to print to PDF.

From the top menu bar, select File, then Print.

From the bottom of the Print menu that opens, select the dropdown PDF, then Save as PDF.

Enter a name and location for the PDF to go on your Mac, then enter any additional information needed (Title, Author, Subject, or Keyword).

Choose Security Options if you would like protect your document with a password.

Click Save.