You can take screenshots while playing media on PlayerXtreme as mentioned in the following steps:
Step 1: Tap on the three dotted line on the top bar
Step 2: Swipe up on the list of options and choose "Screenshot"
Step 3: Tap on the ret dot to take a screenshot.
Step 4: Screenshot will be saved
Step 5: To view saved screenshots go to the library and tap on the Screenshots folder.
Step 6: Your saved screenshots will appear.