Method 1: From the viewer
1. Tap the Overflow button to open a overflow menu.
2. tap Save a Copy from the menu.
3. Tap Identical Copy.
4. Select the file destination when prompt and give the file a new name.
Method 2: From the file browser
1. Tap one of the file browsing tabs, Folders, All Documents or SD Cards.
2. Long press on a file to bring up the file management options. Tap the Duplicate icon to make a copy of a file.
You can also tap the file's Information icon, then tap Duplicate.
3. Long press or tap the Information icon of the newly created file copy, and tap the Rename.