Not sure I know what you mean... 20EUR goes from her to bittiraha, bittiraha then takes a cut and buys bitcoins for the rest from someone who is selling them on some market. Bittiraha then sends these bitcoins to a Bitcoin address that you provide. The Bitcoin system itself knows nothing of the 20EUR, it only registers the bitcoin transaction in the blockchain (public ledger where all transactions are stored) Does this answer your question?