Open the FASTag issuer’s website or mobile app
Log in using your registered mobile number, vehicle number, or customer ID
Select the FASTag account or vehicle linked to the tag
Click on Recharge, Add Money, or Top Up
Enter the amount you want to add
Choose a payment method such as UPI, debit card, credit card, net banking, or wallet
Complete the payment and wait for confirmation
Check the updated FASTag balance in your account
Save the payment receipt or transaction ID for reference