Export raw files with xmp on ipad pro

You can currently export raw files from ipad. When in an image, you use the little export button, Hit the tiny little button to give you settings next to "Export to Files" and select "original". Then hit export to files and select a location, which can be your icloud drive, creative cloud, dropbox, etc. Unfortunately, you don't get the xmp which is really strange actually and a big omission. If you select dng as already noted by @Rob_Cullen , you get a full raw in dng format with the xmp embedded. 

You can if you accept the 'raw' is in the DNG format, with the XMP data embedded.

My iPhone can Export as DNG.

See this Chapter in the link- "you create new image files that include the edits and other metadata changes you’ve made to the photos."

Export photos in the format of your choice

https://helpx.adobe.com/lightroom-cc/using/save-share-photos.html#connectionshttps://community.adobe.com/t5/lightroom/export-dng-files-in-3-easy-steps/td-p/10917524

Adobe rarely, if ever, announce their development plans in advance. Anyone who knows anything would be under an NDA forbidding them to talk about it. You could make a feature request at the official Adobe feedback site (though I expect there's already such a request over there, in which case add your vote): https://feedback.photoshop.com/topics/lightroom-mobile/5f5f2093785c1f1e6cc40875