Should Duties Be Mentioned On Letter- Canadian Immigration Purposes

Dear frnds,
Can anyone help me out with the format of experience letter which is required for Canadian Immigration purposes.
I am bit confused here. The relieving letter i got from my organization (from India) only includes my Job designation along with the joining and relieving dates. So, if someone can tell me if i also need to get the duties mentioned on my experience letter to file my immigration here in Canada.
Awaiting responses.. thanks in advance to all..

Dea Sir
I am enclosing here with my resume for your kind information. i request you to kindly provide me the model of advertising accouts executive experience certificate model for canada immigration and my resume.
Regards
C Kishore Kumar