Hello Valentine,
If your helper text is longer than your form attribute length, then you can hover on it and it will be displayed on multiple lines.
But to natively display it over multiple lines is not possible.
There was an internal request on that topic, but it has been decided to not proceed with it as wrapping the description text would break the form's layout. Therefore, if the text exceeds the field's width, it is truncated with an ellipsis. This behavior applies to both helper texts and custom validation error messages. The text is truncated in these cases to prevent layout issues, and this behavior cannot be changed.
Valentine CARTERON
When creating forms, we have the option to add help text that appears at the bottom of a form field during creation:
Is it possible to display this help text on multiple lines?