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# Required CLI Options
We said before that *by default*:
* *CLI options* are **optional**
* *CLI arguments* are **required**
Well, that's how they work *by default*, and that's the convention in many CLI programs and systems.
But if you really want, you can change that.
To make a *CLI option* required, you can put `typer.Option()` inside of `Annotated` and leave the parameter without a default value.
Let's make `--lastname` a required *CLI option*:
{* docs_src/options/required/tutorial001_an.py hl[5] *}
The same way as with `typer.Argument()`, the old style of using the function parameter default value is also supported, in that case you would just not pass anything to the `default` parameter.
{* docs_src/options/required/tutorial001.py hl[4] *}
Or you can explicitly pass `...` to `typer.Option(default=...)`:
{* docs_src/options/required/tutorial002.py hl[4] *}
/// info
If you hadn't seen that `...` before: it is a special single value, it is <a href="https://docs.python.org/3/library/constants.html#Ellipsis" class="external-link" target="_blank">part of Python and is called "Ellipsis"</a>.
///
That will tell **Typer** that it's still a *CLI option*, but it doesn't have a default value, and it's required.
/// tip
Again, prefer to use the `Annotated` version if possible. That way your code will mean the same in standard Python and in **Typer**.
///
And test it:
<div class="termy">
```console
// Pass the NAME CLI argument
$ python main.py Camila
// We didn't pass the now required --lastname CLI option
Usage: main.py [OPTIONS] NAME
Try "main.py --help" for help.
Error: Missing option '--lastname'.
// Now update it to pass the required --lastname CLI option
$ python main.py Camila --lastname Gutiérrez
Hello Camila Gutiérrez
// And if you check the help
$ python main.py --help
Usage: main.py [OPTIONS] NAME
Options:
--lastname TEXT [required]
--help Show this message and exit.
// It now tells you that --lastname is required 🎉
```
</div>
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