Is there a mitzvah to write a Sefer Torah?

The mitzvah to write a Sefer Torah is one of the 613 commandments, and its primary source is Deuteronomy 31:19: "Now, write for yourselves this song." The Talmud (Sanhedrin 21b) understands that this instruction, given regarding the Song of Ha'azinu, actually refers to the entire Torah: every person is obligated to write, or to commission the writing of, their own Sefer Torah. The Rambam (Laws of Sefer Torah 7:1) rules: "It is a positive commandment upon every man of Israel to write a Sefer Torah for himself." The Shulchan Aruch (Yoreh De'ah 270:1) brings this same halacha. In practice today, very few people know how to write a Sefer Torah with the precision halacha requires — every letter must be formed correctly, without error, on kosher parchment, with special ink. The accepted custom is therefore to fulfill the mitzvah by commissioning a professional Sofer STaM to write the Sefer Torah on one's behalf. Many communities also have the custom that each person writes (or has the Sofer guide their hand in writing) at least one letter of the scroll, to actively participate in fulfilling the mitzvah. Some poskim discuss whether today, when every synagogue already has communal Sifrei Torah, the mitzvah can also be fulfilled by donating toward the writing of a Sefer Torah for public use. This is a practical question worth raising with a rabbi. Beyond commissioning the writing to a Sofer, there is an even higher aspiration: to learn the craft of Sofrut STaM and merit writing, with your own hands, the sacred letters of the Torah. Our sages teach that one who fulfills a mitzvah with their own body and hands reaches a connection different from one who only commissions it to another. Learning sofrut is not just acquiring a trade — it is joining an unbroken chain of generations of scribes who transmitted the Torah letter by letter. If you feel that calling, the real first step is to study with an experienced Sofer and the halachic sources of the craft — before any tool, what's needed is the will to learn. As with any applied halachic question, this article is only an informative introduction — for a practical decision, consult a trusted rabbi.