How do I find out and file if I don't have all the paperwork?

Sorry, I thought I was doing a search so my question was incomplete... My aunt is suffering from mild dementia and I don't believe she's filed her taxes--and she doesn't remember. I can't find any of her paperwork, so I don't know if I can find out if she's paid, or get copies of her 1040s, etc... to see if I can get them filed. Thank you.

Are these your own taxes, or someone else's you are concerned about?