iTunes Confusion

I realize in today's age many(maybe most) are using Apple Music. For my purposes I still like to have most of the music actually on my iPhone.

I recently got a new iMac and for the most part everything is working great.

However on the old Mac I seemed to simply be able to drag new music onto my device or delete old music off of it.

I've found a work around for part one. I can't seem to drag music onto it but I can right click and say "add to device"

If I wanted to remove songs from my iPhone I simply go to the "Music' section under my iPhone which is listed under devices. I would than look for the song and right click and select delete from library(it would only delete from my iPhone and not my iTunes library). However now the only options I have are

Add to Device
Add to Playlist
Create Station
Get Info
Go to
Show in playlist

I'm not sure I know how to delete it now. Even though I have a new iMac I would have had the most up to date versions of iPhone and IOS on my phone, so I am not sure what the change would be? I almost I have something checked/clicked in away that is preventing me from doing this but gosh if I know what it is.

Any help would be greatly appreciated!

Yes Apple does keep changing things, especially in relation to music and photos;
Just follow these steps:
Go to Settings -> General -> Storage & iCloud Usage.
Tap Manage Storage and wait till you get a list of your iPhone apps. ...
Choose Music, then click Edit at the top right corner and All Songs in case you really want to get rid of all your music.
And finally tap the Delete button.
You can select individual albums as well, when you see the tracks list click edit and you can remove individual tracks.