Highlighting The edges of the Complete world

I was wondering how can one create an effect which highlights the complete world like the one we see in borderlands or any other telltale games.
I tried googling a lot however i only found it related to highlighting a specific object. Through that i understood that we need to change post process settings and create a material to highlight. However the thing which i don’t understand is how to do it. I think we have to change the blendable setting in post-process.
If you guys can help me figure out how to do it or point me to a tutorial which does the same i would be really grateful

Thank you

you may want to take a look at epic’s stylized demo.