Tax file for retired person.

Below are my mother's(retired) income detail:

• Pension (12500+12000) of my father's(not alive) & herself,
• few FD on her name and
• Gets rent of Rs. 16000/-(by cheque). 

Now I want to file her tax return, but as she doesn't get Form 16 so how can I file her tax return. We want to show all mentioned above.