1. There is a setting (in 2016, maybe earlier) that does that while you type
Capture.JPG
2. On the Find/Replace dialog, there is a [Special] button that has that plus others. Click [More>>] to see it
Capture2.JPG
3. Recording a macro and using the [Special] button, you get a good starting point
Option Explicit
Sub Macro2()
Selection.Find.ClearFormatting
Selection.Find.Replacement.ClearFormatting
With Selection.Find
.Text = " - "
.Replacement.Text = " ^= "
.Forward = True
.Wrap = wdFindContinue
.Format = False
.MatchCase = False
.MatchWholeWord = False
.MatchWildcards = False
.MatchSoundsLike = False
.MatchAllWordForms = False
End With
Selection.Find.Execute Replace:=wdReplaceAll
End Sub
4. You can also use
Replacement.Text = " " & Chr(150) & " "
for an en-dash, or 151 for an em-dash