Answer for this question you will find in the article below.
At first you need to enter to your Admin CP panel.
After that you need to choose CUSTOM FIELDS menu on the left side panel and select to CREATE A CUSTOM FIELD in a right top corner.
When you clicked CREATE A CUSTOM FIELD button you will get a new page where you can choose Location and Type of your Custom Field.
Also do not forget that you can select your Custom Field to be mandatory or not and you can placed it on registration panel.
If you turn on all this functions and press ADD button you will get next result.
So now you are already know how to create your own custom field on a registration panel.
Thank you for your time!