All current iPad models share the same iPadOS16 Operating System - and all have broadly the same core capabilities. Models essentially differ in their performance and physical attributes. iPad Pro models use FaceID for biometric user-authentication, while other use TouchID.
You can compare iPad models here:
iPad - Compare Models - Apple
The iPad9 is the current entry-level iPad. The iPads Pro are the opposite end of the scale - top of the range, with cutting edge capabilities and hardware. Between these two extremes is the iPad Air5, this model offering a mid-range high performance option. The new iPad10 is cheaper than the iPad Air - and differs in position of the front-facing camera. The iPad mini6 is perhaps an entirely different proposition - offering a smaller form factor and other differences in hardware and ultimate capability.
You can directly compare the specifications of all iPad models here:
iPad - Compare Models - Apple
All current models of iPad support either the first or second generation Apple Pencil. For handwritten notes and sketches, this will be relevant. Ensure that you choose the correct Apple Pencil for your chosen iPad - as they are not interchangeable. Here is the definitive compatibility list:
Apple Pencil compatibility - Apple Support
Due to limitations of internal hardware, the new Stage Manager feature introduced with iPadOS 16.1 is only available for these models of iPad:
- iPad Air (5th generation)
- iPad Pro 11-inch (all generations)
- iPad Pro 12.9-inch (3rd generation and later)
Feature availability is usually limited by system hardware - CPU and available RAM being critical to some advanced functionality.
iPad models supporting Stage Manager (providing full support for an external monitors up to 6K resolution) have an M2, M1 or A12X CPU (upon which the M-series CPUs are reportedly based) - with at least 8GB RAM. The iPad Air4 has only 4GB RAM.
Whichever iPad model you choose, you would be well advised to purchase as much internal storage as your budget might reasonably allow - as internal storage (and other hardware) cannot be changed, upgraded or extended. The available internal storage is fixed for the entire life of the device. If you run out of internal storage for your documents, photos and other data, you will forever struggle and become a source of frustration. It is far better to have more storage than you need, than to need more storage than you have.
A good rule of thumb is to quantify how much data storage you will need - add a healthy margin - then double it. If you are unable to quantify your data storage needs, it becomes more difficult. Whilst I and others cannot cannot make definitive recommendations for your personal needs, objectively I would council against purchase of any iPad with any less than 256GB storage - 512GB offering a greater degree of safety. Also note that for current models of iPad Pro, only the models with 1TB and 2TB internal storage benefit from 16GB RAM; other storage tiers have only 8GB RAM.
Within the Apple Support Communities we see regular tales of woe and disappointment when storage requirements are exceeded, necessitating replacement of the device; by contrast, we never see complaint of having too much available storage. It is relatively easy to fill limited internal storage space; perhaps consider higher tiers of storage as providing room for growth as your needs develop or mature - potentially extending the useful usable life of the device.
Also consider the fundamental functional differences between WiFi Only and WiFi+Cellular models of iPad. Only WiFi+Cellular models include GPS capabilities - which may impact any Apps or features that require accurate and consistent location data, such as Mapping. Purchase of a WiFi+Cellular model does not commit you to using Cellular connections, but provides this flexibility should it be needed. WiFi Only models of iPad have no Cellular or GPS functions at all.
WiFi Only models can only “infer” their location from a database lookup of neighbouring WiFi networks for which the geographic location is known, or the geographic location of your public IP address. For static applications in urban locations, where the location of IP public IP addresses and WiFi networks are known, an “inferred” location can be relatively accurate. However, in rural locations, or when using a Cellular/Satellite/VPN connection, location accuracy of an inferred location [if it works at all] may be very inaccurate.
