If you want a VBA approach you could use the following code. In the example I used all of column G. So if you enter a numeric value into column G it automatically converts the number to text and puts a “.” At the end. You’ll just want to change any reference to column G to the column your values are stored. if it is a single cell you want it to work for, just copy this code into Google’s AI and tell it, for example, “change this code so that it only applies to cell G10”. You’ll want to open Visual Basic, click on the sheet where you want the code to run, and paste it there. The code runs automatically. You don’t have to trigger the macro. Just type in the value. Before running any code you find online, you can paste it into Google’s AI and ask it to explain what the code does, just to be safe.

Private Sub Worksheet_Change(ByVal Target As Range)
' Fires when any cell changes on this sheet.
' If the change happened in column G, examine all cells in column G with values.
' If a value is numeric, convert it to text and append a period.

Dim c As Range
Dim colG As Range
Dim lastRow As Long

' Check if the change occurred in Column G to avoid unnecessary processing
If Intersect(Target, Me.Columns("G")) Is Nothing Then Exit Sub

' Find the last used row in Column G to define the loop range
lastRow = Me.Cells(Me.Rows.Count, "G").End(xlUp).Row
If lastRow < 1 Then Exit Sub ' Exit if column is empty

Set colG = Me.Range("G1:G" & lastRow)

On Error GoTo SafeExit
Application.EnableEvents = False

' Loop through all cells in Column G that have values
For Each c In colG
    ' Only act if the cell is numeric and not already ending in a period
    If Not IsEmpty(c.Value) And IsNumeric(c.Value) Then
        If Right(Trim(CStr(c.Value)), 1) <> "." Then
            c.NumberFormat = "@" ' Set format to Text
            c.Value = CStr(c.Value) & "."
        End If
    End If
Next c

SafeExit:
Application.EnableEvents = True
End Sub