I have Polaris Office installed on my HTC Sense 6, but I cannot delete or find it on my installed apps, Play Store, and even Device Administrators. Though, I can run the app and use it.
How am I going to delete it?
From HTC Rezound (Verizon Wireless)'s FAQ (I know it's a different device, but it's same for most HTC phones),
What is Polaris Office?
Polaris Office comes pre-loaded on the phone and can be used to open and view office documents (Word, Excel, PowerPoint) received in email as attachments or stored on the SD Card. [...]
In other words, it's a bloatware. You need to have root access to uninstall bloatware.
If not, you can still disable it. Since it's not installed as a normal application, it won't be listed as your installed apps. Instead, you have to select "All" tab to list all apps, including bloatware. Then you can find and disable the app from there.
Alternatively, long-press the app from the app drawer (not home screen). There should be "App Info" on the top of the screen. Drag to there and release, and it should open the app info where you can disable it.
If you can run the app and use it this means there is a widget where you can use to enter.
Long press that widget(app icon) from home screen, since long pressing from app drawer just adds it to home screen, choose app info, this will redirect you to the app in the application manager where you will have options to uninstall or clear data...