Perhaps if you told us what TV make and model you have, and what sources you are trying to play, and how everything is connected,  someone on here will be able to help you get Atmos or explain why you can't. 

I’ve seen it from a bunch of different TVs, including LG, Sony, and Samsung TVs. At my own home, I’m getting Atmos played on my Amazon Fire TV Stick 4k, through Dolby Digital Plus on my TCL Roku TV 65r615.

it is genuinely possible. as @John B notes, without more information we can’t offer much useful for your situation except suggest waving a dead chicken over it - that worked for me but YMMV.

@Trinitycall 

Sounds like you’re asking a pre-sales question rather than that you are having an issue. I’ll join the rest and say Dolby Atmos can be played through the Arc. My set is a LG C9 (2019) with Arc.

Cheers!

If, indeed you’re pre-purchase of a TV, get one with eARC, and you should be able to play Dolby Atmos without issue. Currently, there aren’t that many TVs with eARC (yet), but you could look on rtings.com for a list. 

Thought I’d provide an update. Plugged in the new Arcana eARC adapter (to Apple TV, projector, Sonos Arc) and without changing any settings had a 4k HDR picture and Dolby Atmos coming out of the Sonos Arc.

A must buy for people with projectors or non-eArc compatible TVs.

Simple