1
What it actually is
An FX forward locks in an exchange rate today for a trade that settles on a future date — commonly anywhere from a week to a year out.
The forward rate isn't a guess about where spot will be; it's mechanically derived from today's spot rate plus the interest rate gap between the two currencies.
2
Why someone would do this
A company with a euro invoice due in six months doesn't want its dollar cost swinging around with the exchange rate between now and then.
A forward locks the rate today, so budgeting for it becomes a known number rather than a bet.
3
Who's actually doing this
Corporate treasurers hedging future receivables and payables are the classic users, alongside anyone with a known future FX cashflow.
Asset managers hedge a foreign bond position this way; exporters price a contract months in advance using the same trade.