If I have already submitted DDPI, will I still need to enter CDSL TPIN & OTP while selling shares on Pocketful?

CDSL TPIN & OTP are only required in the absence of DDPI. The DDPI document authorizes us to automatically debit shares from your demat account whenever you sell them on Pocketful. While Pocketful's DDPI facility is safe, as a broker, we'd still advise our clients to use eDIS as it gives them more control over their holdings. 

For more info checkout: SEBI Circular