Writing a letter stating salary for someone who will use it to get a riba-based loan
Question

                There is an employee who works for the government in a financial department. Naturally his work includes paperwork for employees’ salaries and other tasks, and that includes giving employees letters with details of their salaries when the employee requests that. But some of them use this letter to take out loans from the bank. Is there any sin on the employee who provides this certification, knowing that this is part of the nature of his work?.
Praise be to Allah.There is nothing wrong 
    with writing a letter stating salary details for employees who request that, 
    unless it is to be submitted to a riba-based bank with the aim of taking out 
    a loan. In that case it is not permissible to write it, because that is 
    helping them to disobey Allaah, and to commit a major sin. 
The Standing Committee 
    (15/58) was asked about an employee in the copy department of a university 
    who wrote letters for the university employees so that they could take 
    riba-based loans from one of the banks – is that permissible? 
They replied: 
It is not permissible to 
    make these copies or write these letters if the one who is doing that knows 
    that the letter will help the person to engage in riba-based transactions, 
    because of the general meaning of the hadeeth according to which the 
    Messenger of Allaah  (peace and blessings of Allaah be upon him) cursed 
    the one who consumes riba, the one who pays it, the one who writes it down 
    and the two who witness it, and he said: they are all the same. Narrated by 
    Muslim in his Saheeh. And because of the general meaning of the verse 
    in which Allaah says (interpretation of the meaning): 
“Help you one another 
    in Al‑Birr and At‑Taqwa (virtue, righteousness and piety); but do not help 
    one another in sin and transgression”
[al-Maa'idah 5:2]
And Allaah knows best.