Confused in softwares of ubuntu and kubuntu
 

I wanted to shift to kubuntu LTS but I dont know if kubuntu have different softwares or special softwares as there are some software have 'K' in their name and some have 'G' in their name?
What difference does desktop environment like kde and gnome makes rather than look?

These two desktops each come with a lot of applications, that are not just the desktop. KDE as you suggest, the app names start with a 'k'; kcal, kjots, kfloppy, the list goes on. Gnome is the same. There are many apps with an equivalent in the other desktop.

Some apps will install with the basic desktop, others may need to be installed in addition. For kde, you can go to www.kde.org and look at the Applications that are available.

Desktops in linux is a matter of choice. You can install as many as you have disk space for. 'buntus' have a default desktop, depending on the first letter. Your choice, which you run. The rest of the system is the same code.

Is it true that software of kde will not run in gnome?
Will you please suggest me must have and best softwares of kde.

Is it true that software of kde will not run in gnome?
Will you please suggest me must have and best softwares of kde.

If you are running any of the 'buntus', you can install kde apps with a Gnome desktop. Synaptics will find all the pre-req libs, and other code necessary to run each app you install. You wind up with a mixed system. I have done this, both ways, since there are some Gnome apps I like, and KDE apps I like.

I don't like Gnome, on my netbook I have XFCE installed, along with Gnome. I have added several Gnome apps, they work as they should. Even though I run XFCE most of the time.

Hope this helps.