The time required to obtain a presumed warranty replacement may be influenced by many factors, including but not limited to:
- The iPad model - and availability of an equivalent device
- Your country/region
- The manner in which you have sought replacement - such as visiting an official Apple Store, or an Apple Authorised Service Provider (AASP)
- Shipping
Whether you have visited a Store or AASP, you should have received documentation that provides information about the process/procedure. This may indicate a estimate for the time required to complete the process.
Similarly, if using Apple's mail-in service, you should have received a shipping kit with which to return your existing iPad. The mail-in service obviously takes additional time for shipping and assessment of the returned item.