can iPad download to sd card

What specifically are you attempting to “download” to, or from, your iPad using an SD Card? While SD Cards can be used just like other types of external storage, they are generally used to import photos from a camera.

Firstly, you’ll need to connect at suitable SD Card reader to your iPad - for which you’ll find guidance in the [frequently overlooked] iPad User Guide:

Connect external storage devices to iPad - Apple Support

Direct import of photos from your camera SD Card to your Photo library is possible - subject to a couple of caveats:

• the SD Card must be correctly formatted as FAT, FAT32 or exFAT (FAT64)
• stored photos are stored within the expected DCIM folder

Import photos using Apple camera adapters - Apple Support

If you are unable to use the direct photo import feature, you can still manually access and copy photos from the SD Card using the iPad’s built-in Files App. To do so, just open the Files App - and in the Sidebar you will see your SD Card in the list of Locations. If necessary, open the sidebar by tapping the sidebar icon at top-left of the Files App Window. Photos can be copied to the iPad Photo Library, or copied to a folder of your choice either on your iPad or elsewhere.