Batch Import Photos
From the Lightroom mobile app home screen, click the + icon to import your photos and choose Camera Roll. Locate the images you want to import, and hold down on the first photo. Holding the photo down activates the multi-selection process, so you can keep selecting as many photos you want to import. Once you're done, click in the check icon.
Batch Export Photos
From your photo gallery in the Lightroom app, hold down the first photo you want to import to activate the multi-selection feature. Next, select all the photos you want to import, click on the Share button and choose how you want to export your photos. That's it!