I owe IRS and when I filed my tax I want to send a check on the July 15 to pay but now I want to have agreement to pay every month how I change now

If you already filed your tax return, and indicated that you would separately mail a check, and if you now don’t want to mail a check for the full amount, what you do is:

Go to the IRS website and apply online for a payment plan. There will be a nonrefundable application fee. In most cases, you will get approval immediately online. Then, begin making payments according to the approved schedule.

https://www.irs.gov/payments/payment-plans-installment-agreements

If you did not already file your tax return, you should still indicate that you will pay by mail, and then apply for the payment plan online directly at the IRS website. If you apply for a payment plan through TurboTax, the nonrefundable application fee will be higher.