You are several years too late to receive a refund for a 2015 tax return. A refund you could have received for 2015 has been forfeited. If you owe tax due though, the IRS wants to be paid. You can seek paid tax help locally to prepare a 2015 return or you can use the paper forms and prepare a 2015 return by hand to mail in.
2015
Form 1040 https://www.irs.gov/pub/irs-prior/f1040--2015.pdf
Form1040 Instructions https://www.irs.gov/pub/irs-prior/i1040gi--2015.pdf
Form1040A https://www.irs.gov/pub/irs-prior/f1040a--2015.pdf
Form 1040A Instructions https://www.irs.gov/pub/irs-prior/i1040a--2015.pdf
Form 1040EZ https://www.irs.gov/pub/irs-prior/f1040ez--2015.pdf
Form 1040EZ Instructions https://www.irs.gov/pub/irs-prior/i1040ez--2015.pdf
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
