Please explain what you mean by "hyphenation suggestions." Once you choose the hyphenation settings (in the Control Panel menu, or in styles, InDesign hyphenates automatically following the rules you set. You can override the hyphenation: The best way is by using the No Break command.
Maybe you mean in the User Dictionary. Choose Edit > Spelling > User Dictionary. Enter a word in the Word field, and click Hyphenate.
maybe I'm thinking back to Quark days or really old versions of indesign.. there used to be a feature under Type for "hyphenation suggestions" you could highlight a word, choose this, and it would give you a little pop-out window (not sure of format) or something SHOWING you how you COULD hyphenate, what PROPER hyphenation would be.. for example, I'd highlight the word "automatically" and the window would show me auto-ma-ti-cal-ly.
It was for when you are UNSURE how a word should hyphenate (kind of LIKE the word I used as an example.. I'm NOT sure that is right!) and if you are forcing in a discretionary hyphen you would know you were putting it in the right place.
(Dredging into old dusty brain archives...)
Yes, I think that was a QuarkXPress feature that I never used. As I said, you can edit your User Dictionary to change the hyphenation for a word in the dialog box I mentioned.
I don't recall ever seeing or using that in Quark, but Scribus and MS Word have features that loosely match what you're describing. I don't think InDesign ever had it.
I thought I'd add my 2cents worth; for longevity. I too just wondered where this feature was as I remember and used it often back in my days of QuarkXpress, very useful.
You can see the hyphenation alternatives that InDesign uses under Edit>Spelling>User Dictionary>Hyphenation, after selecting the word.