Issue price (also called final issue price or cut-off price for that issue) is the price at which IPO shares are actually allotted. It is determined by the book-building process — the highest price at which the entire issue can be sold across all categories, based on the demand book the BRLM compiled during the bidding window.
For book-built issues, the final issue price for retail bidders who bid at cut-off is the upper band (or whatever lower price the book settles at). For NII / HNI and QIB bidders who specified a particular price, allotment is at the final settlement price regardless of what they bid — provided their bid price was at or above the settlement.
Issue price is locked in once subscription closes and the book-building process completes. The RHP often disclosed the issue size in number of shares; the rupee issue size is computed from this final issue price.