Welcome to the Spotify Community and thanks for posting.
On desktop, you can of course remove a track from a playlist whilst listening to it. At current, it's not possible to remove a track from your playlists on mobile, only add to it. Why not show your support to this idea over in our ideas board? The more Kudos your idea receives, the better! The ideas with more Kudos are looked into by our team of Developers and when possible are added as new features 🙂
I hope this helps out. If you do have any further questions, do let me know!