Fill cells in a column with the same term then stop filling when data ends

WIN 10, Excel 2016.  I volunteer IT at a homeless center.  We use a sign in sheet drawn from Salesforce, downloaded into Excel then massaged by a macro to produce the printed list.  They want one column to have the term “shelter out” in every cell one column to mark where the client stayed the night before.

I can get the column to fill each cell correctly but I need it to stop filling when there is no more data in the other columns.  So, one day the list will have 651 clients, the next day it might have 670.

Below is the fill function from the macro.  How do I get it to stop when there is no data in adjoining cells?
Sub Macro1()
‘
‘ Macro1 Macro
‘

‘
Range(“J1”).Select
ActiveCell.FormulaR1C1 = “out apt shelt”
Columns(“J:J”).Select
Selection.FillDown
End Sub

Thanks for the help!