How do I change the background image of the boot up screen?
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You mean the lock screen? Changing Lockscreen and Wallpaper on Plasma 6 - Help - KDE Discuss
He’s talking about refind, a boot manager. 
But probably referring to Plymouth.
All the refind settings are in the refind.conf on the ESP.
The option is banner.
I will allow myself to click it as a solution because there is no better solution as reading the manual.
Agreed. I’ll just leave this here for posterity as well: rEFInd - ArchWiki
Any way to be Sudo in KDE?
This should answer the question you might really be asking:
sudo nano /boot/efi/efi/refind/refind.conf
Many applications in KDE Plasma are polkit-aware and will request a password when needing to perform privileged actions. However, starting the application itself will not prompt you for a password right away.
For instance, you can use kwrite or kate to open any of the plain text files under /etc, and the file will load into editor without any problem. However, if you then make a modification to the file and you attempt to save the modified version, then you will be prompted for a password.
Thanks,odd KDE doesn’t ask the password & open the folder.
It doesn’t have to if the permissions allow read access to everyone.
Note: /boot/efi is a vfat filesystem, and thus the permissions are emulated at mount time, because vfat does not have a way of storing them.
One can usually edit a system file using Kate.
Elevated permissions are not initially needed when opening a file for editing, but when you save it, your password is then requested.
Unfortunately, this doesn’t work if the file you wish to edit is on an $esp.
Opening refind.conf with a console based editor (and using sudo) is then the most viable option, an example being nano as illustrated in my previous post, but micro and others will likely work as well.
The efi folder is locked in KDE. I can not see the files in it.
That’s right;
Then change the permissions, Nick. 
sudo mount -o remount,rw,nodev,noatime,sync,fmask=0022,dmask=0022,codepage=437,iocharset=ascii,shortname=mixed,utf8,tz=UTC
This is a temporary remount, which will give you the ability to — as root or by way of sudo — edit the files on the EFI system partition.
This visibility will not persist across reboots, because /boot/efi normally gets mounted with the options set in /etc/fstab.
Get a bad usage errpr.
My bad. I should have completed that command with the proper device or mountpoint.
sudo mount -o remount,rw,nodev,noatime,sync,fmask=0022,dmask=0022,codepage=437,iocharset=ascii,shortname=mixed,utf8,tz=UTC /boot/efi