How to add registration field?

How can I add first_name and last_name to the registration fileds?

According to https://docs.thememylogin.com/article/53-legacy-adding-extra-registration-fields :

First, copy?/wp-content/plugins/theme-my-login/templates/register-form.php?into your current theme’s directory. Then, edit the newly copied template, adding the fields you wish to collect.

But there is no such php in that directory path?

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