Hey there,
If you are still in touch with your ex-employer then try to obtain the reference letter from him, otherwise from your department head, HR or whoever had the access to issue the official LOR on the company letterhead.
If, its not possible to get the LOR printed on the company letterhead, then you can get a customized LOR on the plain paper (an affidavit) declared by your immediate Manager or Colleague, who had worked with you during that employment period. It should be duly attested and notarized along with a copy of the business card, employee ID of the declarer.
Note: Reference Letter of an employee must contain the following details:
- Employee ID number (if any)
- Employee Name
- Company Name
- Designation
- Work Tenure
- Working Hours (per week / per month)
- Annual Compensation
- Job Duties
If any of the above mentioned detail such as:
Salary, Work Hours, Different job positions etc., is missing then you're supposed to include the supporting documents in order to validate your claim regarding that factor.
(The supporting documents are - Offer Letter, Joining Letter, Payslips, Salary Certificate, Salary Increment Letter, Promotion Letter, Form-16, ITR etc.)
Moreover, as you have mentioned that your company is already closed, so I believe there would be some official announcement, legal agreement or any news regarding that. Try to obtain these documents and append it along with your employment docs. You may also ask your ex-employer for these things or get it mentioned on the Reference Letter by him. Get it all done and you're good enough to go.
Hope it would help you.