So I’m not only new to Scrivener, but I am fairly new to a Mac computer. Is there a way to ‘add’ a word to the memory of the program? Like with windows word, if you created a name you could ‘add’ it to the program so that it wasn’t highlighted as a badly spelled word, it was recognized forever after lol.
Thanks! - LadyEchoLynn
Found by searching this forum.
Since Macs handle spell checking in the same fashion that Word, and most other programs do, something that might be a factor here is if you got an Apple mouse with your Mac, or if it’s a laptop—and you are in either case faced with this thing that appears to only have one single button. In fact their devices have all kinds of actions, but some need to be enabled, and most are triggered with different swipes, gestures or even how hard you click, rather than buttons.
Pull down the menu in the top right, select System Settings, and in the Mouse or Trackpad section, look for options that pertain to enabling a “secondary click”. This is what Apple refers to as right-clicking (since left-handers may want to left click as the secondary option). Even though there isn’t a button there, if you click with a finger on only the right side of the mouse, it will “right click”. On a trackpad, you can set it to do this when tapping or clicking with two fingers instead of one.
So now that you can use context menus like you’re probably used to, spell checking should be demystified system-wide. 
Of course there is also the Edit ▸ Spelling and Grammer ▸ Show Spelling and Grammar menu command, and shortcut. This will present a more typical dialogue box with buttons that will walk through all the things it thinks are mistakes.
Somewhat adjacent to system spell check: while you are in System Settings, you may also want to check the Keyboard section out, and click the Edit... button on your Input Sources. This weirdly hidden area has some important features to check out. Personally I find a vanilla Mac install to be an infuriating writing experience, with it jumping all over the place suggesting what I want to write, changing words I’ve already written and so on. It seems tuned for people that aren’t typists, but maybe I just don’t understand the appeal of this kind of stuff. If you want it to only record the letters you type in, there are settings here to turn all that stuff off.
Thanks for those tips, AmberV. I’m a new user of a MacBook and still struggling with its peculiarities and those trackpad and keyboard settings have fixed a few things for me.