From the dashboard, Click on user icon > Account Settings.
To customize mandatory field settings, Click on required fields tab.
This page allows you to customize the fields based on your liking except the system default fields. For example, If you wish to have address line two in move-in then enable “Admin Portal” checkbox and enable “Admin Mandatory Fields” if you to have this as mandatory field. By same way you can customize the customer portal move-in fields as well.
Click on save button.
Now, you can see the address line two fields has been created and marked as a mandatory field.