You can manually 'autofit' your column or you can use VBA to do it automatically. To manually autofit your column after data entry, position your mouse over the *right* border of the column letter at the top until it changes to a vertical line with left and right facing arrows. Then double click your mouse. This will autofit that column.
Or, you can use this VBA solution to do it automatically. This example solution that parses column E. If your column is not 'E', change the "E:E" reference to your column reference, i.e. "B:B", "M:M", etc
Then, copy this event handler, modified as required, to the clipboard (highlight the event handler, right click inside the highlighted area, and 'Copy'):
Private Sub Worksheet_Change(ByVal Target As Range)
If Len(Target) > Target.ColumnWidth Then
Columns("E:E").AutoFit
End If
End Sub
Select the worksheet containing the column to fit and right click the sheet tab at the bottom.
Select 'View Code'.
Paste the event handler into the white editing area to the right (right click inside the area and 'Paste').
Close the VBE (red button - top right).
Save the workbook as an Excel Macro-Enabled Workbook to retain the VBA functionality when subsequently reopened. Archive or delete the non-VBA version of the workbook to avoid confusion.