A block format consists of the whole letter being typed single spaced and left justified with a double space in between paragraphs. A modified block letter will have the same single spaced and left justified layout but the date and closing should be tabbed. Lastly, semi block refers to indented paragraphs while being left justified. You will need to display your address as well as the address of your employer you are writing to.
In the body of the letter you should explain who you are in relation to the company you are writing to. After that you should formally request the salary certificate and explain in detail why you need the certificate as evidence. Politely express your appreciation for them to get back to you as soon as possible and sign off.
You should keep in mind that a salary certificate displays the details of the salary structure of the company your work for. In addition, they are usually only issued when an employee needs to send it as evidence when applying for a bank loan or any other money lending institutions. Moreover, if in any case you are asked to provide a salary certificate you need to contact your employer to obtain one for you.
There is no fixed format for a salary certificate, as it differs between various companies. You should not get this confused with a Form 16 which is used in order to calculate the tax which is payable to the government at the end of the financial year.