How do I permanently remove the Reader thing on my iPad?

Go to Settings > Apps > Safari > Reader, and turn the switch Off for All Websites. Then you can turn on the Reader for each individual website if you wish.

Hide distractions when reading articles in Safari on iPad - Apple Support (KE)

Reader is part of Safari on iPad, and is not removable.

To set Reader to not open automatically for a particular website, tap the computer-like icon on the left end of the Safari address bar, tap the three dots ⋯, scroll the list of options, and select to disable the automatic use of Reader for the current website.

Related details: Hide distractions when reading articles in Safari on iPad - Apple Support

Can you provide more details? What is the complete name of the application? What kind of file is the 'reader thing' trying to read.

to delete an app on the iPad press and hold on the icon until it starts to giggle and then tap on the '-' minus sign and a dialog box will appear asking if you want to delete the app or just remove it from the home screen.

Hope this helps.

Paul