Sofer

A sofer, sopher, sofer SeTaM, or sofer ST"M (Heb: "scribe", ; plural of "sofer" is "soferim" ; female: "soferet") is a Jewish scribe who can transcribe sifrei Torah (Torah scrolls), tefillin (phylacteries), and mezuzot (ST"M, , is an abbreviation of these three terms), of the Five Megillot and other religious writings. 
By simple definition, a sofer is a copyist, but the religious role in Judaism is much more. Besides sifrei Torah, tefillin, and mezuzot, scribes are necessary to write the Five Megillot (scrolls of the Song of Songs, Book of Ruth, Book of Esther, Ecclesiastes, and Book of Lamentations), Nevi'im (the books of the prophets, used for reading the haftarah), and for "gittin", divorce documents. Also, many scribes function as calligraphers—writing functional documents such as "ketubot" "marriage contracts", or ornamental and artistic renditions of religious texts, which do not require any scribal qualifications, and to which the rules on lettering and parchment specifications do not apply.
The major halakha pertaining to "sofrut", the practice of scribal arts, is in the Talmud in the tractate "Maseket Sofrim". In the Torah's 613 commandments, the second to last is that every Jew should write a sefer Torah before he dies. ().
Qualifications and education.
A sofer must be religiously observant, of good character, and knowledgeable about the laws concerning sofrut. It is a common misconception that one has to be a rabbi in order to become a sofer, which is not required by Jewish law.
People who want to become ritual scribes usually learn from another expert scribe by undergoing Shimush (Apprenticeship), since it would be impossible for someone to be a scribe without any actual practice. The hardest part about learning to be a sofer is not the calligraphy, but, rather, remembering the thousands of laws that apply to sifrei Torah, tefillin, mezuzot, and all the other texts that are written on parchment.
Some people who want to become ritual scribes learn at the "Vaad Mishmereth STaM", with the option of receiving a certificate. (This is an international organization whose goal is to protect the halachic and artistic integrity of the scribal arts. It is located in Jerusalem and Bnei Brak in Israel, as well as in Brooklyn, New York, United States.) Certification of this sort is not a halachic requirement, nor does it necessarily guarantee the quality of a particular sofer's work. This process does however ensure that a certified sofer has received the proper education and is a recognized expert in the field of sofrut.
Texts teaching sofrut.
The main texts from which soferim learn the scribal art include the "Keset Ha-Sofer", "Chasdey David", Mishnah Berurah (24-45), Mishneh Torah (Hilchot Tefillin u'Mezuzah v'Sefer Torah, Hilchot Tzitzit), "Mishnat Hasofer", "Mishnat Sofrim", "Likkut Sifrey Stam".
Women and sofrut.
Forming the basis for the discussion of women becoming soferim, Talmud "Gittin" 45b states, "Sifrei Torah, tefillin and mezuzot written by a heretic, a star-worshipper, a slave, a woman, a minor, a Cuthean, or an apostate Jew, are unfit for ritual use." The rulings on mezuzot and tefillin are virtually undisputed among those who hold to the Talmud. While Arba'ah Turim does not include women in its list of those ineligible to write Sifrei Torah, some see this as proof that women are permitted to write a sefer Torah. However, today, virtually all Orthodox (both Modern and Ultra) authorities contest the permissibility of a woman's writing a sefer Torah. Yet, women are permitted to inscribe Ketubot (marriage contracts), STaM not intended for ritual use, and other writings of "sofrut" beyond simple STaM. In 2003, Canadian Aviel Barclay became the world's first known, traditionally trained, female sofer. 
Among non-Orthodox Jews, women have written Torah scrolls since the early 2000s. In 2007 Jen Taylor Friedman, a British woman, became the first woman to scribe a sefer Torah. In 2010, the first sefer Torah scribed by a group of six women (from Brazil, Canada, Israel, and the United States) was completed; this was known as the Women's Torah Project. Since then, other women have written Torah scrolls. As of 2014, there were an estimated 50 female sofers around the world.
Documents written by scribes.
Besides Torah scrolls, tefillin, and mezuzot, scribes are also necessary for the writing of the Five Megillot (scrolls of the Song of Songs, Book of Ruth, Book of Esther, Ecclesiastes, and Book of Lamentations) and Nevi'im (the books of the prophets, used for reading the haftarah), and for "gittin" (divorce documents). In some communities, especially Chaim Kanievsky's community in Bnei Brak, soferim also write the other books of the Bible, such as Psalms or the Book of Ezra. This was promoted in 19th-century Jerusalem by Rabbi Shemuel Shelomo Boyarski.
Calligraphy and lettering.
There are many rules concerning the proper formation of letters that must be adhered to if a written text is to be deemed religiously valid. The Ashkenazi, Sefardi, Chabad (Lubavitch), and Mizrahi Jews each have their own script for forming the letters, though the same rules apply throughout the text. Generally, regarding sifrei Torah, none of these groups would consider that these differences would render a Torah "posul" (ritually unfit or invalid).
The documents must be written on properly prepared parchment or vellum known as klaf.
Many scribes also function as calligraphers—writing functional documents like ketubot, or ornamental and artistic renditions of religious texts—which do not require any scribal qualifications, and to which the rules on lettering and parchment specifications do not apply.