Paleo-Hebrew script
Before the square letters, Hebrew used a Canaanite linear alphabet closely related to Phoenician.
What paleo-Hebrew is
An older letter-shape set for the same 22 consonants. Inscriptions (for example the Gezer calendar and Siloam tunnel inscription) and some biblical-period seals use it. After the Babylonian exile the Aramaic-derived square script became the usual Jewish book hand.
In later Jewish books
Some Dead Sea Scrolls write the Tetragrammaton in paleo-Hebrew letters inside a square-script manuscript. A few medieval and modern display uses exist, but a printed Tanakh and a Torah scroll are square script.
the Name, sometimes drawn in paleo shapes in Qumran copies
What a learner needs
You do not need paleo-Hebrew to read BHS or a ḥumash. It matters for inscriptions, some scroll photographs, and the history of the alphabet.
Read next
The alphabet then and now
Twenty-two consonants, five final forms, and a script that shifted from paleo-Hebrew to the square letters used today.
The Dead Sea Scrolls and Hebrew
Scrolls from the Judean Desert give Hebrew (and Aramaic) copies from around the last centuries BCE to the first century CE, without Masoretic pointing.
Reading the Torah scroll
A sefer Torah is consonants only, in square script, on parchment, chanted with a memorized melody.