Karlie here from the Shopify Support Team! It sounds like you're looking to add local pickup as an option for your customers. Local pickup can be enabled from within your Shopify Admin if your store has 20 or less locations, has multiple location inventory enabled, and has multi-origin shipping enabled. This feature would allow you to set up a shipping rate, called Local Pickup, where your customers can choose to pickup their order at your store at no extra shipping charge.
To set up a local pickup shipping option, you can follow the below steps:
You'll want to go over our help guide on local pickup to make sure that you have all of your bases covered and to understand how local pickup will work with your online store, you can check out our step by step help doc, here to read more.
I hope this has answered your question. If not, or if you have any further questions please let me know. I will be happy to help!