The onsite marketplace is decentralized therefore it is up to each party to confirm the transaction. As stated before, the default transactions are on ravencoin testnet. This will help people new to crypto and blockchain, learn how it works, as well as let people learn meCo tools.
When a transaction is completed, an email is sent to both parties and they will get the TXID (confirm) needed to confirm it was actually executed. If you are new to RVN, you will use an explorer ( i will suggest this for tRVN but you can find your own also; https://rvnt.cryptoscope.io/)
When transaction are done off site, meCo will be unaware and will send no email.
The default onsite being the RVN chain, means that if you experiment with other currencies, the TXID will not currently verify. This is very early stages and this confirm verifications, will eventually match the chosen currency; in the mean time, play around and learn how crypto works and get an early understanding to how the economic revolution will change your world... enjoy..