If you are happy to take my suggestion-
The following documents are mandatory for each work experience declared:
- a reference or experience letter from the employer, which
- should be an official document printed on company letterhead (must include the applicant’s name, the company’s contact information [address, telephone number and email address], and the name, title and signature of the immediate supervisor or personnel officer at the company),
- should indicate all positions held while employed at the company and must include the following details: job title, duties and responsibilities, job status (if current job), dates worked for the company, number of work hours per week and annual salary plus benefits;
You need "a" reference or experience letter which should be an official document printed on company letterhead (rest mentioned above). You cannot provide a separate letter for job duties which is not a official document and not printed on company letterhead. You should provide a single letter with all required details.
If this letter cannot be provided then you can have a letter written on a plain paper which is signed by your supervisor and it should be notarised. In that case you have to prove that you have tried to obtain a letter form your HR but it was denied and also you have to submit other documents such as payslips, tax return, appointment letter etc. You have to explain the whole situation in a Letter of Explanation.
If you do not want to go through all these hassles then try to get
One official experience/reference letter from HR comprising all IRCC requirements.
Hope it helps. Good Luck!