My mother receive social security benefits and she asked if I could file for her. I want to know if I file for her will I get audited next year

What do you mean by "file for her"?

If you mean file HER tax return, that is not needed, if SSI is the only source of income.

If you mean CLAIM her as a dependent, that IS allowed if you provide more than half of her total support.

So if she does get ssi as her only income it is OK to file her as my dependent and I will not be doing anything illegal... the reason I ask is because she came up with the Idea prior but I thought she could file on her own.

You will be doing it legal IF and only if you provide more than 1/2 of her support.

So if audited you have records and can prove you provided income to her for at least 1/2 of her support

Ok thank u

Fr Chuck has it right; you must be bale to prove that you provide more than half of her total support, which is normally NOT a problem if she lives with you or if you pay her rent and utilities.