Applying for shares in an IPO, or bidding for shares in IPOs does not guarantee that you will get the shares.
It's a bidding process so the amount of bids received in each category, the price paid by investors, etc. will all affect how much shares are allotted.
After the IPO closes the registrar prepares a Basis of Allotment'. This document contains information about the bids received at various prices by investors and the pattern of allotment.