Esim for tourist

How do i buy a prepaid Esim ,without monthly plans

Those two things are mutually exclusive.  There is only "monthly service" plans available.

https://www.att.com/prepaid/plans/

You can purchase one month of prepaid service, just make sure you do not enroll in auto pay, or turn auto-pay off while you are still in the United States. Cannot stress that enough.

AT&T will not ship you a QR code for an esim. You will have to enroll in AT&T prepaid with a physical SIM card, or go to an AT&T store to get a QR code for an esim.

Thanks for the details. Appreciate it