Maybe try this:

Sub CountWordOccurrences()
    Dim WordToFind As String
    Dim WordCount As Long  Dim i As Long
    Dim FoundRange As Range
    ' Get the word to find from the user
    WordToFind = InputBox("Enter the word to find:", "Find Word")
    ' Exit if the user cancels the input box
    If WordToFind = "" Then 
        Exit Sub
        ' Make the word case-insensitive for the search
        WordToFind = LCase(WordToFind)
        ' Loop through each word in the document
        For i = 1 To ActiveDocument.Words.Count
            ' Check if the current word matches the word to find
            If LCase(ActiveDocument.Words(i)) = WordToFind Then
                WordCount = WordCount + 1
            End If
        Next i
        ' Display the result in a message box
        MsgBox "The word '" & WordToFind & "' occurs " & WordCount & " times in the document.", vbInformation
    End If
End Sub