http://yomixio76f7bnurcrqrhoud5moeu4bvlgukkylixgh2teqllg3mjrqyd.onion/en/blog/post/how-bitcoin-getting-traced
To do this, it accesses the buyer's wallet data and sees that three Bitcoins, for example, were taken from there. The network also accesses the seller's wallet and now see that three Bitcoins were sent to him. The network confirms the purchase because it can match the data from the two wallets, and the transaction takes place.