TouchWiz: it's got a lot better in recent years, less buggy and not so much of a storage- and resources hog, but it's the UI haters are just gonna keep on hating. We advise you to give it a chance, but if you just can't then read on below. (You might also like our Galaxy S8 review.)
You've come to this article looking for a way to ditch TouchWiz, and the reality is unless you are prepared to root the phone and flash a custom ROM that isn't going to happen. But you don't have to look at TouchWiz every day, and no-one is forcing you to use any Samsung apps.
The solution, therefore, is simple: install a custom launcher. The difficulty is finding one you dislike less than you do TouchWiz.
If you just want to clean things up and get a purer Android experience, the Google Now Launcher may be a good place to start. We also like Nova Launcher. Also see: Best Android phones 2017
Install a custom launcher on Samsung phone
• Open the Google Play Store and search for Google Now Launcher, Nova Launcher or another free launcher app
• Tap Install, accept the pop-up about permissions, then press Open once the installation is complete
• You'll be prompted to choose a Home app, so select the launcher you just installed. TouchWiz will no longer be visible on your Samsung phone
Of course, it may not be the interface itself that bothers you, but the preinstalled apps and bloatware. The best way to get rid of these or minimise their impact on your experience is to reset your phone (be sure to back up all your important data first), then as you go through the setup procedure be careful not to enable any Samsung services.
You can reset your phone by going to Settings, General Management, Reset, Factory data reset.
Though you cannot uninstall any preinstalled apps, you can clear their caches and disable them in the Settings, Apps menu.
If you're absolutely determined to get rid of TouchWiz once and for all, see our advice on rooting Android.