Hi, I am getting back into healing and hearing about click casting. Are these macros that allow you to cast via mouse over?
Or is this an addon?
I am thinking it is the first option which would make it easier to cast abilities and not have to click the unit frame to cast your ability.
If this is a macro could someone share and example.
Edit:
No wonder I was confused they were probably talking about Clique addon.
#showtooltip SPELL NAME
/cast [@mouseover] SPELL NAME
Click casting is built into the UI now, but I don’t necessarily remember where the settings are. Also, pretty sure Clique will continue to work into Midnight?
Edit: Clique is updated for 12.0. You can install it and get it set up now and it’ll continue to work
Thank you so much, I don’t remember this being in game back when I healed in TBC.
So it is both a macro and an addon. Good to know!
The macro I included is just for mouseover casting, it doesn’t actually include the click to heal functionality. I simply misread your original post, which is my bad 
So…
That macro will cast a spell at my mouse but I still need to hit the associated button. Which is still awesome.
But are you saying I can make a macro that will do all of that when I just click my mouse button over a friendly target? That seems nuts!
I personally don’t like click casting so I cannot tell you the specifics of how it works using the in game systems. The addon Clique however lets you bind spells to your mouse buttons, just mouseover & click, then you can assign modifiers (like shift, alt, etc.) to change what spell will be cast.
Going to have to download it and try it out. Currently I click the unit frame of the target I want to heal then cast the ability. Being able to mouse over and click to heal will be a game changer for me. Especially with my most used spells.
In Options → Combat, check “Mouseover Cast”
Then it doesn’t require macros by default.
Best use for me is that it works on party/raid frames.
It can be hard to find the party member you want in the heat of combat, but you can mouseover their party frame and cast whatever spell without having to click-target them (which allows you to keep dpsing the boss or whatever else you may be doing).
Options > Key Bindings > Click Casting. It’s limited to solely the Left and Right mouse buttons, though, so all the side buttons on a gaming mouse won’t work. Plus, Blizzard limits what spells can be bound. Last I checked, you can’t bind Cleanse spells for some reason.
I use VuhDo right now, but not sure if they’ll keep updating after the add on purge with 12.0
The addon Clique is, IMO, the way to go. Its simpler, easier, and faster than macros and the built in click casting doesn’t allow the use of every button that you may want to. Clique just works and works well (and still does in Midnight)