Changing app icons not working for all apps. Android noob

[_Lee_]

I'm trying to change app icons and have Good Lock which works great ith designing my own icons, but when it comes to downloading an icon pack from the store or wherever the icons don't all change. The likes of YT and FB still remain in their original state along with quite a few others. I understand I'll have to download a third party apk or something to get them to work fully, is that right? Can anyone advise what to download specifically as I'm a but lost with it all with being new to it all!

[BandOfBrothers]

Some of the apps will always stay with their original icon as this has been set this way by the icon pack developer @_Lee_  I think some app icons can't be changed. 

I personally stay away from apk files as these can potentially negativity impact the phone.

If i can be of any further help please don't hesitate to ask  😎 

[_Lee_]

OK thanks for the heads up