See the store itself
Self-service returns and exchanges, six ways to sell, and a checkout that runs on your own payment account.
Sell to consumers in the EU or EEA and "do I have to accept this return?" has a specific legal answer most of the time — and it isn't set by your returns policy. Here is what the statutory right of withdrawal requires, when the clock starts, and the narrow cases where it genuinely stops applying. A plain-language summary, not legal advice: confirm anything that matters against your national transposition and your own counsel.

The 14 days run from a different point depending on what was sold:
Physical goods — from the day the consumer (or someone they nominated) physically receives the item. For an order split into several deliveries, from receipt of the last item; for a regular subscription of goods, from receipt of the first delivery.
Services and digital content — from the day the contract is concluded (i.e., the day of purchase), since there's no physical delivery moment to anchor to.
The directive carves out specific exceptions (its Article 16), and the ones that come up most for an online seller are:
Digital content not on a physical medium — a downloadable file, an instant digital unlock — loses the withdrawal right the moment delivery begins, but only if the consumer gave express, informed consent to immediate delivery and explicitly acknowledged that they'd lose the withdrawal right by doing so, both before delivery starts. Skip the consent-and-acknowledgment step and the ordinary 14-day right still applies to the download.
Services fully performed before the 14 days are up — lose the right once performance is complete, again only with the consumer's prior express consent to that immediate performance and their acknowledgment of losing the right as a result.
Goods made to the consumer's specifications, or clearly personalized — genuinely bespoke or custom items are exempt. This turns on whether the item was actually made-to-order for that buyer, not on which product category or selling mechanism you used to sell it.
Sealed goods unsealed after delivery, where return is unsuitable for health or hygiene reasons — exempt once unsealed, not before.
A handful of narrower cases — goods that deteriorate or expire quickly, sealed audio/video/software once unsealed, newspapers and single-issue periodicals, accommodation/transport/car rental/catering tied to a specific date, and a few others.
The full 14-day right applies as described above — plan for it as a normal cost of selling physical goods online, not an edge case.
The right can be waived, but only if you capture the consumer's express consent to immediate delivery and their acknowledgment of losing the right — before they get the file, not in your general terms after the fact.
Once a service has been fully delivered with the consumer's consent, the statutory right lapses on that service — but a booking that hasn't happened yet is a separate question of your own cancellation terms, not of withdrawal.
The 14-day withdrawal window applies to the subscription contract itself when it's first signed. That's a different thing from your own "cancel any time" terms for an ongoing subscription — one is a statutory first-14-days right, the other is an ongoing feature you may offer regardless.
Likely exempt as personalized goods — but confirm the item was genuinely bespoke to that buyer, not simply a made-to-order variant of a standard catalogue item, before you treat a request as exempt.

Self-service returns and exchanges, six ways to sell, and a checkout that runs on your own payment account.
"No transaction fees" can mean three different things. A plain breakdown of processing, platform and subscription fees.
What "connect your own Stripe or PayPal" actually means, and why it's different from a platform that collects and pays you out later.