$attributeSet = $this->attributeSetFactory->create();
        $attributeGroupId = $attributeSet->getDefaultGroupId($attributeSetId);

        $customerSetup->addAttribute('customer_address', 'address_email', [
            'type' => 'varchar',
            'label' => 'Email',
            'input' => 'text',
            'required' => true,
            'visible' => true,
            'user_defined' => true,
            'sort_order' => 1000,
            'position' => 1000,
            'system' => 0,
        ]);

        $attribute = $customerSetup->getEavConfig()->getAttribute('customer_address', 'address_email')
            ->addData([
                'attribute_set_id' => $attributeSetId,
                'attribute_group_id' => $attributeGroupId,
                'used_in_forms' => ['adminhtml_customer_address', 'customer_address_edit', 'customer_register_address'],
            ]);
        $attribute->save();`