it can be in the below format
[Company Letter Head]
[Date]
To whom it may concern,
[Applicant] has been employed by [employer] from [start date] to [end date], in the position of [position or job title]. His/her monthly/annual salary was [salary]
In this position, he/she had the following duties and responsibilities:
[list of duties and responsibilities]
Additionally, [any additional information]
Please do not hesitate to contact me if you require any more information
Sincerely,
[Name of supervisor]
[Signature of supervisor]
[Business card of supervisor attached if possible]
[/list]