SketchBook is now free and doesn't need a login to 'turn it on'. Just go to the AppStore or Google play to download it.
If you have access to the OLD phone, you can move the files over manually.
Android: See Step 9.
NOTE: On Android, all the sketch files (.tiff format) are in /Autodesk/SketchBook3 folder.
https://forums.autodesk.com/t5/sketchbook-forum/android-sketchbook-tips-and-tricks/td-p/9385407
NOTE: A preview of file is then saved into the "Gallery (Photos)" of phone.
iOS: Use iMazing software. Plug in phone and backup (SketchBook) to desktop computer and then plug in NEW phone and export SketchBook back to iPhone/iPad. All Sketches should be intact on new device.
https://imazing.com
David Lau