How to file taxes for a senior citizen 74 years old

Hi there,

 

I am trying to help a friend who is 74 years old and only receives SSI. I heard that she needs to still file her taxes in order to be eligible for Obama medical care even though her only income for past 9 years so far has been only SSI which she suspects may probably discontinue (along with her medicare) shortly due to some new asks from SSA that she is unable to address. Appreciate your help on how to go about, where to start with her taxes (any links, etc.) and any pointers. Thank you.