Selfnamed does not offer automatic recurring or subscription-based billing.
Each order needs to be placed manually, meaning there are no automatic charges – you are only billed when you actively place an order.
If you have products that you order regularly, you will need to re-purchase them each time. A quick way to do this is by using the reorder option on any previous order:
Go to your Selfnamed profile → Orders
Find the order you'd like to repeat
Click the three dots next to the order and select Re-order