Not Understanding Radio Buttons

In the “Fields” settings, or overridden for a single form, under “Allowed values:” you can enter one option per line, in the format key|label, like

|select one…
label 1
key 2|label 2
key 3|label 3

The key will be saved in the database and sent by email, and the label is shown in the form.

If there is no key as in the second line, the key is the same as the label

In the first line, the key is empty, so if the field is marked as required, if you don’t select another option, you get the message that the field is required.

Hope it helps