I owe taxes for the past 5 years. Do I have to create separate payment plans for each year or one payment plan for total amount I owe for all 5 years?

Do not send all of those tax returns to the IRS in the same envelope.  Make sure you send them separately, each in its own envelope.  Use a mailing service that will track them so you know they are received by the iRS--such as certified mail, UPS, or Fedex.  You will hear from the IRS about the penalties you owe for filing so late if you have owed taxes for 5 years.  When you know the amount, you can probably set up a payment plan for what you owe.

Well there's a Installment Agreement Request (Form 9465) that I was told to fill out but I'm unsure if I have to fill out this form for each individual year or one form for the total amount I owe for all 5 years.

Form 9465 allows you to address multiple years. Form/Instructions: <a rel="nofollow" target="_blank" href="https://www.irs.gov/uac/about-form-9465">https://www.irs.gov/uac/about-form-9465</a> See Part I, Line 1

Yes ... read the form carefully ...