I don't just need numbering, I need dot after that.

You need dot after what?

After you enter any number into any cell in column A?
Format column A as Custom, Type = 0\.
Now whenever you enter any number into column A, it is displayed like '1.', or '85.', or '999.'. At same time, it is really a number, i.e. when you sort your table by column A e.g. in ascending order, then e.g. 11 > 2. It's value really doesn't contain any dots, the dot after number is only displayed. And whenever you refer to Column A cell values in formulas, you have to use numbers without dot. And when you delete row(s), values in column A are not recalculated automatically.

All other solutions (where cell value contains a dot) assume you use some formula in column A. And this means you don't enter values into column A - they must be calculated by formula (or inserted by VBA script, but closest events you can use for this are worksheet events, which are running whenever you change something in any cell in worksheet (this may slow down your workbook performance considerably)). And such value is really a text, i.e. when you sort your table by column A e.g. in ascending order, then e.g. '11.' < '2.'.