Please follow the below mentioned steps based on the UPI app you use.

Google Pay

1. Download the Google Pay app on your device.
2. On your mobile device, open the Google Pay app .
3. At the top right, tap your Profile picture.
4. Tap Bank account.
5. Tap Add bank account.
6. Select your bank and add further details.

Paytm

1. Download the Paytm UPI mobile app on your device.
2. Select your preferred language and verify your mobile number.
3. You will receive an SMS to verify your mobile number.
4. Now, select the bank account that you want to link to your UPI account. Ensure that the mobile number registered with your bank is the same as the one you entered earlier. Your bank account details will now be fetched from the bank using your mobile number.
5. Enter your details such as name, mobile number, date of birth, etc., if requested.
6. Your virtual ID/ UPI ID will be created.
7. The next step requires you to enter a password of either 4 or 6 digits, as per your preference.
8. Your UPI account will now be successfully created!

PhonePe

1. Download the PhonePe app on your device.
2. Tap your profile picture on the app’s home screen.
3. Select the bank account under Payment Methods section or tap View all payment methods to select the bank account.
4. Tap + next to the relevant UPI handle.
5. Create a UPI ID of your choice or choose one from the available options.
6. Tap 'create' at the bottom of the screen to create a unique ID.

Alternatively,

1. Tap your profile picture on PhonePe’s home screen.
   
2. Tap UPI IDs under the Payments Settings section.
   
3. Tap Continue under the Better Manage your UPI IDs section.
   
4. Create a UPI ID of your choice or choose one from the available options.
   
5. Tap 'create' at the bottom of the screen.