This article explains the process of how to apply for IPO through ASBA using HDFC Bank.
With the Net Banking Option, even the physical form is also not required and an online IPO application can be done without any wet signature and completely online. Securities and Exchange Board of India (SEBI) has notified a list of banks through which online IPO can be applied which are known as SCSBs (Self Certified Syndicate Banks).
For applying for an online IPO using HDFC Bank an Investor has to follow the following steps:

Login to your HDFC Online Net Banking account
On the left side, click on “Request” & Select the “IPO Application” Option in the drop down
Now, click on “Continue” on the next tab
Select “IPO Application”. You will be directed to the HDFC Securities page where you can check the current IPO issue names. Select the IPO and Click on Apply.
Now, this will redirect you to the order placement page.
Select Investor Status as IND RETAIL. Click on OK.
Depository Details – Select Depository as CDSL. SAMCO is a Depository Participant (DP) with CDSL. Enter DP Name as SAMCO. Enter your 16 digit Beneficiary Account Number.You can get the demat account number from SAMCO Star. After Login, on top-right corner, click on the dropdown with the client’s name on it & select “My Profile” as shown below:
This shall open a new window, where you can check the “Demat account number” or “DP ID” or “DP Beneficiary ID”. It would be a 16 digit number, which would be combination of 8 digit DP ID (for SAMCO customers, this would be fixed at 12054200) and 8 digit DP Beneficiary ID which is unique for each client.
Please enter “SAMCO Securities Limited” for DP Name, and your own name in case of “Beneficiary ID”. Alternatively, the DP ID can also be taken from the transaction cum holding statement sent via mail by SAMCO Securities Ltd.
Confirm these details to complete your IPO Application.