An entry signal is the specific condition a trader's strategy requires before opening a trade — a candlestick pattern, an indicator crossover, a break of a key level — while an exit signal is the equivalent condition for closing it, whether at a profit target, a stop-loss, or a reversal signal. Clearly defining both in advance, before entering a trade, is what separates a rules-based approach from purely discretionary guessing.
A strategy is only as testable (and as disciplined to follow) as its entry and exit signals are precise and repeatable.
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Guide
Why a Signal Disappears Before the Bar Closes
The right-most bar is still being built, so everything drawn from it is provisional. What redraws honestly, what confirmation costs, and which setting decides what you are looking at.