If you want to insert the symbol with a macro then and format it as 24 point red then
Code:
Sub InsertCheck()
Dim oRng As Range
Set oRng = Selection.Range
oRng.InsertSymbol _
Font:="Wingdings", _
CharacterNumber:=-3842, _
Unicode:=True
oRng.End = oRng.End + 1
oRng.Font.ColorIndex = wdRed
oRng.Font.Size = 24
oRng.Collapse wdCollapseEnd
oRng.Select
Selection.Font.Reset
End Sub