One bitcoin equals 100,000,000 satoshis. Multiply BTC by that number to obtain satoshis, or divide satoshis by it to obtain BTC. This unit conversion requires no market price. Fiat valuation is a separate calculation with a named currency, observation time and relevant execution costs.
A payment QR code makes data entry easier but does not decide that the recipient or request is correct. It can contain an address, amount, invoice, link or application-specific instruction. After scanning, inspect what opened and review the actual payment again before authorizing it.
Repeated use of one Bitcoin address can link payments and complicate invoice matching without a clear record. New addresses can help organize receipts and reduce direct aggregation, but do not erase published history or guarantee anonymity. Review monitoring and backup coverage alongside the receiving workflow.
A Bitcoin address prefix describes aspects of receiving format, not who owns it or whether a particular service supports it. Before sending to an address beginning with 1, 3 or bc1, check the network and both products' support, then compare the entire value with verified receiving instructions.
Whether a Bitcoin payment can be stopped depends on its stage, who controls the funds and what the wallet means by cancel. A service may stop a request before broadcast; a wallet may attempt a conflicting replacement. A confirmed payment to another party has no general sender recall button.