If the document exists the style leave else need to create the character style.
after that can create more style like this.
Code:
Sub CStyle()
Dim objDoc As Document
Dim cbolditalic As Style
Set objDoc = ActiveDocument
Set cbolditalic = ActiveDocument.Styles.Add("*italic", Type:=WdStyleType.wdStyleTypeCharacter)
With cbolditalic.Font
.Name = "Times New Roman"
.Bold = False
.italic = True
.Subscript = False
.Superscript = False
End With
Dim rngStory As Range
For Each rngStory In ActiveDocument.StoryRanges
Application.ScreenUpdating = False
With ActiveDocument.Range
With rngStory.Find
Options.DefaultHighlightColorIndex = wdYellow
.ClearFormatting
.Replacement.ClearFormatting
.Text = ""
.Replacement.Text = ""
.MatchWildcards = True
.Format = True
.Forward = True
.Wrap = wdFindContinue
.Font.Bold = False
.Font.italic = True
.Font.Subscript = False
.Font.Superscript = False
.Replacement.Style = "*italic"
.Replacement.Highlight = True
.Execute Replace:=wdReplaceAll
End With
End With
Next rngStory
Application.ScreenUpdating = True
End Sub