Hi
adityachaurasiya905Thank you for your asking. Kindly provide the information below so that we can better assist you.
1. Your current firmware version
Settings>System>About Phone>Software information>Build Number
2. Which firmware do you want to update? If you want to OTA to Android 10beta, please update your Android 9 to the latest version first, then perform the manual update to Android 9.
#Update Guide
https://www.asus.com/support/FAQ/1009748/