Will someone be able to tell me what the mailing address is to mail my tax return to in the state of Missouri?

On the Filing Instructions page should be the address for where to mail the federal tax return.

Go to this IRS website for where to mail a federal return, with or without a payment - https://www.irs.gov/filing/where-to-file-paper-tax-returns-with-or-without-a-payment

If you live in MISSOURI ... and are filling Form 1040

mailing no payment in then mail to :

Department of Treasury
Internal Revenue Service
Kansas City, Mo 64999-0002

Mailing with a payment mail to:
Internal Revenue Service
P.O.Box 931000
Louisville, KY 40293-1000