Is it permissible to send money via the bank within the framework of external commercial dealings, and is it permissible to purchase foreign currency on one day and give its owner the money a week later?

Transferring money through banks is permissible if they are Islamic banks that do not deal with usury, such that the amount is transferred from one account to another in the sender's country without the addition of any usurious transaction. However, dealing with usurious banks is not permissible.