The CV font has to be suitable for the purpose. A suitable font is Times Roman or a similar business font.
The size should be 10 or 11 point, depending upon your printer and your chosen CV layout. As a check for size with 2.5cam (1 inch) left and right hand margins there should be 15-18 words on a line.
The CV font needs to be easy to read and gentle on the eyes. Don’t be tempted to use a smaller font so that you can cram more onto the page. You cannot possibly include every detail in your CV structure. The text must not look squashed within your CV layout. There must be sufficient white space around things to be kind to the eyes.
The CV format needs to be professional and leave enough white space on the page. Key factual information is what is important as you can always elaborate on the finer details at an interview.