PDF should work without installing more apps (if the phone variant come with Google services).
- Are you trying to open pdf files on websites, from Google Drive, or files that are stored locally on the phone?
- What exactly happen if you transfer a pdf file via USB or Bluetooth, and then find and tap it in the Files app on the phone?
Please state the phone variant (TA-????) and Android version if further troubleshooting is required.
The phone variant number (TA-????) and more technical information is found in Settings > System > About ...
Did you try pdf files on different websites and different files on the phone?
The error message word for word, please?
Is the phone set up with a Google account?
Are all apps updated in Play store > My apps?
Did you try another pdf on the Internet, in the Chrome browser on the phone - as suggested by the error message?
Also please consider the other questions in my previous post.
I suggest ask a skilled friend for help in real life if the error persist.