So I saw XFCE online and it looks so cool and I’m tired of Windows like look. I installed XFCE but I don’t know how to use it. I can’t do it on login screen. What should I do?
If you have installed it on Zorin, then when you Login, look for the ‘cog’ next to password. If it has installed you should see xfce. You may also want to take a look at Sparky Linux. I gave 5.7 a try a while back and that has a unique DE chooser - you go to a DE chooser app, select that, apply it, log out then choose the new DE. Enlightenment was the only buggy one and only E-live out of any distro has managed Enlightenenment really well. However it’s included documentation includes links to a page that I would not want kids looking at - whether his .iso has been injected in one of the hyperlinks I don’t know.
Worked! Also I found out that my vpn and blueman icons were missing because of gnome! They are back! I also like xfce way more than gnome! It even has an add launcher function! I was trying to do that on gnome for days! Thanks for help man!
Glad to help where I can sir! You the customer will always be King in my book! 
The alternative I was going to ask you to try was to use Gnome-Tweaks to disable the Zorin Panel which leads to the traditional Gnome Panel at top of screen (and hopefully the icons) but it appears to be buggy in 18.04 too. Glad you are sorted friend.
This amuses me because I thought about suggesting you try XFCE4-Panel instead of Gnome Panel.But I did not want to be too hard on Gnome. 
I STRONGLY prefer XFCE desktop environment over the others. KDE is as good, but a bit more complicated…