Since currencies are traded in pairs, it’s impractical and not very useful to draw a pure USD currency chart. Instead we have the option of drawing (or rather having the software plot for us) a chart of the USDJPY pair, or the AUDUSD pair, since it is only possible to quote a currency in terms of another. On the other hand, there are some forex charts that take weighted average of such currency pairs to derive an overall index for a currency. The famous USD index, is a good example.
In forex, investors use leverage to profit from the fluctuations in exchange rates between two different countries. The leverage that is achievable in the forex market is one of the highest that investors can obtain. Leverage is activated through a loan that is provided to an investor by the broker that is handling the investor’s or trader’s forex account.