i want to create coupon code in magneto something like below 1:discount 1% of sub-total up to a maximum of Rs. 300
i can not find any such way to do via magento backend
Go Marketing -> Promotions -> Cart Price Rules -> Add New Rule
Check Screen-shot here
After save above use USER12 code and Run Magento command
php bin/magento s:up
php bin/magento c:c
php bin/magento c:f
I Hope This Helps You.
Install this extension, it is working to set maximum discount limit.
https://www.magepsycho.com/magento2-discount-limiter.html