Magento 2 Don’t require First Name & Last Name on Registration

First of all you should remove the is_required option from the lastname attributes in the customer entity and address entity:

UPDATE `eav_attribute` SET `is_required` = ‘0’ WHERE `eav_attribute`.`attribute_id` = 5;

UPDATE `eav_attribute` SET `is_required` = ‘0’ WHERE `eav_attribute`.`attribute_id` = 7;

Ref : https://magento.stackexchange.com/questions/176823/magento-2-how-to-make-lastname-optional-in-customer-registration-form