Go to DK Plugins → WC Local Pickup. Set the label and placeholder shown for the required pickup-location field, then save the settings.
Edit a WooCommerce coupon and enable its local-pickup option. You can also enter a custom message to display in the cart while the coupon is applied.
Use the classic WooCommerce checkout. The pickup field and validation use its PHP hooks; this plugin does not add the field to the Checkout block. Configure a WooCommerce Local pickup method in the applicable shipping zone before relying on coupon-based rate filtering.
When the coupon is applied and local pickup is available, other shipping rates are removed. The pickup-location field is shown and required for local-pickup checkout.
The selected pickup location is saved with the order and shown on the thank-you page, in the WordPress order admin, and in WooCommerce order emails.