I am working on an application that through which I want to sell some event Tickets.
Can I use PayPal for this purpose, and will Apple approve the app using other t
No, you can't. The Store Review Guidelines, which every iOS app must match in order to get passed by Apple, clearly states that: - you are not allowed to use "a system other than the In-App Purchase API (IAP) to purchase content, functionality, or services" for payment (11.2) - it is not permitted to "us[e] IAP to purchase physical goods or goods and services used outside of the App"
Indeed, there is an API from Paypal for this purpose, but, as stated above, Apps using it will not pass the Review.