To make UPI payments from an account, you need to set a UPI PIN for that account. 

To set your UPI PIN:

1. Select your bank account under the Payment Methods section by scrolling to your right. Alternatively, you can tap View All Payment Methods to view the bank accounts you've added on PhonePe.
2. Tap Set UPI PIN under that account. 
3. Enter your Debit/ATM card details for that account.
4. Enter the 6-digit OTP that you receive through SMS on your registered mobile number. 
   Note: If you enabled SMS permissions, PhonePe will auto-fetch the OTP. You can enable PhonePe to auto-fetch your OTP in your PhonePe Settings >> Apps & Notifications >> PhonePe >> Permissions. 
5. Enter the 4-digit ATM PIN for your Debit/ATM card. 
6. Enter the 4 or 6 digit UPI PIN that you wish to set for the account. 
7. Confirm the PIN by entering it again. 
8. Tap Confirm.