A doji formation in forex trading is a candlestick pattern that occurs when the open and close prices of a trading period are almost equal, creating a small or non-existent body with long upper and lower wicks. This formation indicates indecision in the market and can signal a potential trend reversal. Traders may use doji formations as a signal to enter or exit a trade, depending on the context of the market and other technical indicators. However, like any technical analysis tool, doji formations should be used in conjunction with other forms of analysis and not relied upon solely for trading decisions.