Account currency is that the GL account in which currency do you want to maintain. if you DECIDED that you want maintain in company code currency, you can post any currency in that account. If not, you want to maintain separate currency for that GL then exchange rate difference will come because the conversion rate.

Balance in local currency - some GL account can't be maintain on open ITEM basis and can't in FOREIGN currency LIKE CLEARING account and discount account etc., in such case you can assign this indicator to show the balance in local currency.

Account currency is that the GL account in which currency do you want to maintain. if you decided that you want maintain in company code currency, you can post any currency in that account. If not, you want to maintain separate currency for that GL then exchange rate difference will come because the conversion rate.

Balance in local currency - some GL account can't be maintain on open item basis and can't in foreign currency like clearing account and discount account etc., in such case you can assign this indicator to show the balance in local currency.