To Label Objects in External References (Xrefs)

Click Insert tab Reference panel Attach .
In the Select Reference File dialog box, select the DWG to insert into the current drawing.
In the External Reference dialog box, set the Insertion Point values (X, Y, and Z) to 0.00.
Set the Scale values (X, Y, and Z) to 1.00.
Set the Rotation angle to 0. Click OK.
Now you can label the xref data.
Click Annotate tabLabels & Tables panelAdd Labels menuNotes to open the Add Labels dialog box.
Select the feature to label and the label style(s) to use.
Note: Labels for View Frames and Matchlines are not supported through xrefs.
Click OK and pick the label locations.