Default terminal in Lubuntu 18.10 is QTerminal. Somehow, I couldn't find any setting for transparency anywhere.
I found almost similar question here. Lubuntu terminal background tranparency
Unfortunately, that's meant for LXterminal in Ubuntu 18.04.1 LTS.
Would it be possible to do that in Lubuntu 18.10's QTerminal? If yes, please let me know how.
If not, what is the alternative?
UPDATE
Found the setting as advised by DK Bose, but it didn't work.
It's there in File > Preferences:
And here's how it looks with 20%:
Edit:
QTerminal should now show the desired transparency.
Editing your Compton preferences