What is the process for filing if I haven't filed taxes for the 2022 tax year?

Well, this isn't actually for me, it's for my 94 year old mother.  She's usually quite efficient on staying up on all this with her tax specialist, but 2022 was an extremely challenging year in terms of health issues.   I casually suggested a few days ago that she file an federal extension for the 2023 tax year (Texas, no state income tax).  She revealed that she hadn't filed her 2022 tax returns,  and had lost touch with her account (or more appropriately, her account lost touch with HER.) Because she's retired, she has fixed limited income and one or two interest bearing accounts and says she usually has to pay taxes but it's typical never over $300 or so.  I countered with the fact that non-filing penalties could triple the actual amount she owes.   What are the steps she (or I, more than likely) take to get her current on her 2022 tax filing?