Hedging through invoice currency.
The firm can shift, share, or diversify:
Shift exchange rate risk by invoicing foreign sales in home currency
Share exchange rate risk by pro-rating the currency of the invoice between foreign and home currencies
Diversify exchange rate risk by using a market basket index
Hedging via lead and lag.
If a currency is appreciating, pay those bills denominated in that currency early; let customers in that country pay late as long as they are paying in that currency.
If a currency is depreciating, give incentives to customers who owe you in that currency to pay early; pay your obligations denominated in that currency as late as your contracts will allow.