Here some certificates of Language courses taken; to give you an idea. 

    It can state the class hours (sometimes with the statement xxx hours-level) , date of issue, grade in letters, percent grading, etc. Director of the institution (course), teacher or tutor, seal of the Gov. Education Department, accreditation number from the Educ. Dept. (if any).    As you can see, it can be simple or have some information more, it´s up to you.   

http://christian.rottensteiner.info/languages/2002_lsc/

http://www.teflindia.in/fees.shtml

http://www.expana.net/about_resume_bec_certificate.php

http://www.global-english.com/courses/-tesol-training-tefl-training-tefl-courses-accredited-tesol-tefl/180-hour-level-2-tesol-with-business/
In the tab "certification" there are two sample certifications.