I have a cellular/wifi enabled iPad Pro 11″, Model No. MU162LL/A with a 256GB drive and I LOVE LOVE LOVE my Logitech Slim Folio Pro (Link).
It has the ability to fold easily, type on, and even fold away to enable screen writing. There is nice space for the pencil to magnetically attach to the case for storage/charging. I travel 50%-75% of the time and can adjust the screen in various positions to watch a movie or compose an email. It is Bluetooth and requires charging via USB-C, but very seldom as it has great battery life.
There’s this article that came out that has some other choices, but for the price and utility, this one is darn good.

