[Magento2.2]Creating a custom Customer attribute through module upgrade (UpgradeData.php)

[Magento231]

This blog will help you to create your own customer attributes in Magento 2 programmatically which allow adding more specific properties.
First of all, you should have your own Magento 2 Extension. See how to create your module here.
Step 1: Create InstallData.php file
Step 2: Modify data input for each kind of attribute
Step 3: [Optional] Customize layout
Step 4: Enable your module and see the result
You can read this tutorial : How to create Customer Attribute in Magento2