What it does
Pashta is a light disjunctive. It marks the end of a sub-phrase within a larger clause, signaling a small pause rather than a major stop. Pashta is almost always followed by Zakef Katan within a word or two, so when you see Pashta, look ahead: the next stop is on its way.
Where it appears
In most longer verses. The phrase pattern Mahpach-Pashta-Munach-Zakef Katan is one of the staple sequences of Torah reading and it shows up many times per chapter. Pashta and its lead-in Mahpach work as a pair.
How to remember it
Pashta means "simple" or "straight." The mark itself is a single straight diagonal slash above the letter, with no curve or hook. There is one critical rule: Pashta always sits on the last letter of its word, regardless of where the accented syllable is. This is what visually distinguishes Pashta from its lookalike, Kadma.
Example from the Torah
Common phrase
Pashta sits on the last letter of יְהוָה֙. The mark is preceded by Mahpach on וַיְדַבֵּ֤ר (the conjunctive that serves Pashta), and is followed shortly by the next major stop. Together this is the classic Mahpach-Pashta unit that bookends so many verses.
Hear the melody
A synthesized rendering of the melodic shape, not a vocal recording. For a baal koreh's voice on a full aliyah, PocketTorah is a great free resource.
Hand signal (simanim)
Often confused with
Pashta and Kadma use almost identical symbols. The difference is position: Pashta always sits on the last letter of its word. Kadma can sit on any letter. If the slash above is on the final letter, it's Pashta; otherwise it's Kadma. This is the most common confusion in trope learning, and the position rule is the only reliable shortcut.