Can I use 20W adapter for iPhone 8 Plus

Hi!

Yes, absolutely.

As long as the charger you want to use has a 9.0V or 5.0V output option, then you're fine. A 20W charger is the iPad charger... you can use it just fine.

You can even use 30W chargers... I sometimes use my MacBook charger for my iPhone.

Just make sure that it has a 5V or 9V option, because otherwise you run the risk of frying your phone.

Hope this helps!

-flef

You can. the iPhone 8 Plus supports fast charging