Statement of Purpose to Canada High Commission

cover letter usually means STATEMENT OF PURPOSE. it's a letter to VISA CONSULAR/OFFICER stating atleast answers of the following questions

# Why do you wish to study in Canada in the program for which you have been accepted?
# What is your overall educational goal?
# Why are you not pursuing a similar program in your country of residence/citizenship?
# What research have you done into studies in your country of residence/citizenship?
# How will this program enhance your employment opportunities in your country of residence/citizenship?
# What ties do you have to your country of residence/citizenship?
# If it has been more than 2 years since you have left full-time education, please provide your C.V. (resumé).
# In the case of a minor applicant, what are your reasons for studying in Canada? What is your parents'/guardians' immigration status in their current country of residence?

You can add reasons for your study gaps, job description(if applicable). but dont burden with over explanation. you may start and finish this letter like

(Address of Embassy or High Commission) (Date)
Dear Consular Officer

Subject: Personal statement in support of student permit application.

I, __________, amapplying for a study permit for Canada as I have secured admission in (SUBJECT) at (INSTITUTE/University) in (STATE), Canada.
FINISHING
Therefore, I kindly request to grant the study permit and oblige me.

Yours Sincerely

(NAME)

The lawyer may said about the following things (you'll find in the CHECKLIST)

1. If some or all of your funds are provided by a sponsor (either parents or a third party), a notarized declaration of sponsorship, income tax assessments, and proof of citizenship/permanent residence
2. If someone other than yourself or your parents is providing funds, a letter of explanation as to the reason this person is assisting; number of persons living in this person's household; proof of this person's relationship to you;