A family of Microsoft word processing software products for creating web, email, and print documents.
Word does not have a built-in way to do that. You might run the following macro (a modification of the code in https://word.tips.net/T000519_Word_Count_for_a_Section.html)
Sub WordCount()
Dim NumSec As Long
Dim S As Long
Dim Summary As String
NumSec = ActiveDocument.Sections.Count
Summary = "Word Count" & vbCrLf
For S = 1 To NumSec
Summary = Summary & "Section " & S & ": " & _
ActiveDocument.Sections(S).Range.ComputeStatistics(wdStatisticWords) & _
vbCrLf
Next S
Summary = Summary & "Document: " & _
ActiveDocument.Range.ComputeStatistics(wdStatisticWords)
MsgBox Summary
End Sub