Scandisk connecting to iPad or iPhone

That would largely depend upon the type of “Sandisk Product” that you are attempting to connect. If you are attempting to connect a USB Card Reader, then you will need an appropriate USB adapter that is suitable for both the device and your model of iPad/iPhone.

If you intend to use a USB Memory Stick (Thumbdrive), SSD or Camera Memory Card, connection of external storage devices is certainly possible with some caveats...

To be recognised by iPadOS, the attached USB storage device must be formatted to FAT, FAT32, exFAT, APFS or HFS+ with a single partition. As the iPad has limited power capabilities, dependent upon the Storage Device, an external power source is often required.

If your iPad Pro has a Lightning port, you will need to use an Apple Lightning to USB3 Camera Adapter to connect USB devices to the iPad. This adapter has both a USB 3.0 Type-A connector and an additional Lightning port to supply power, from your Power Adapter, to both the iPad and connected device. The Power Adapter must be rated at 12W or more. This adapter will also be required for iPhone.

• Lightning to USB 3 Camera Adapter

https://store.apple.com/uk/xc/product/MK0W2ZM/A

If you have an iPad Air4, or 2018/2020/2021 model of iPad Pro with a USB-C connector, you may need to utilise a powered USB hub (i.e., it has its own source of power) - connecting both the iPad Pro and the storage device to ports on the hub.

The external storage device will obviously require an appropriate USB3 cable to connect to the USB port of the Lightning to USB3 Camera Adapter, or USB hub if used.

Some additional information can be found here:

Connect external devices or servers with Files on iPhone - Apple Support

https://www.imore.com/how-use-external-hard-drives-your-iphone-or-ipad

If you are using an SD or microSD card, there are specific Camera Card adapters that can directly connect to your iPad.

I hope this information proves to be helpful in outlining your options.