Below is the examples of to whom it may concern letter that might be useful when you are looking for it. Make sure that the arrangement will not be that far from the sample written below. Any way you are still free to edit and customize it.
To whom it may concern,
I confirm that (name) is/was employed as (position) with this organisation from (date) to (date/the present day), and was/is paid (salary, plus bonus and benefits as applicable).
Their job of (position) carries the following responsibilities (describe briefly the job). (Name) is skilled in (details of skills) and is also (characteristics - eg reliable dependable, a good communicators, etc).
I would happily re-employ (name) as I consider him/her to be a valuable member of the team, who consistently achieved good results and delivers all expectations.
Yours faithfully, etc