Dim strtxt As String, Tbl As Table, Rng As Range
strtxt = "SomeText"
Set Tbl = ActiveDocument.Tables(1)
Set Rng = Tbl.Cell(i, 3).Range
With Rng
  .End = .End - 1
  .Collapse wdCollapseEnd
  .Text = strtxt
  .Font.Bold = True
End With