I am relatively new to Linux. I was using gnome-shell for a few days, but decided to go for kde-plasma. However, whenever I log in, I am met with this screen instead of the more traditional lock screen. Please help regarding this!
This seems to be a broken or generic/stock GDM theme?
KDE often uses SDDM as its login manager, but it isn’t at all required. I don’t think Plasma would touch GDM itself.
The specific distro used here might be useful, as this will be specific to their packaging and configuration setup. It really isn’t related to KDE itself, but someone in here might know what to do, once we know more of your OS details.
I imagine if you removed Gnome stuff after adding Plasma, that might do something like this.
If so, you can install SDDM
Yeah, I installed sddm, but sddm doesn’t seem to be taking any effect. Whenever I reboot, this screen is appearing!
You need to enable it.
How to do that will be specific to your distro, which we don’t know yet 
Before you run into further problems, might I suggest whiping the entire gnome thing and do a kde ( kubuntu whatever) reinstall. Gdm is still there and you’re running, as far as gdm is concerned, kde in a session.
It’s solved. Turns out, it was running sddm, just needed some new themes, and it’s running like it’s intended to. Thank you very much
