1. Tap one of the file browsing tabs: FoldersAll PDFs or SD Card.

2. You can then access the Move icon using two different methods:

Method 1: Long press the file to show the Move icon.  

Method 2: Tap the file's Information button, to show the Move icon.

3. After tapping the Move icon, a folder navigator dialog will appear. Navigate to you desired target folder, and then tap Select.