Hi, assuming you mean you wish to change the background of explorer, try Quizo's Qttabbar (freeware).
Highly configurable, it's the only real way to change explorer, and adds tabs.
Make sure you follow the installation instructions and how to enable it in explorer.
Recommended by a number here.
For other areas, you need a small registry hack, supported by a saved theme reapplied after resuming from sleep or hibernation- else teh background colour (below) is lost as widely reported by those who've tried it. (I've never read of anyone else solving that). I used that approach in Win 8 and now in Win 10 after MS removed the relevant dialogue.
Note the background changed from MS off-white - a well-known registry hack.
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Control Panel\Colors]
"Window"="250 250 177"
[HKEY_CURRENT_USER\Control Panel\Desktop\Colors]
"Window"="250 250 177"
(I'm also using Aeroglass- a little transparency, colour and borders).