Shalom, How can one accomplish the Mitzvah of writing a Sefer Torah? Can one get the Jewish community in one’s neighborhood involved?
To answer your question, allow me first to first address your question theoretically and then practically. There is a dispute among the poskim if we actually must write a Sefer Torah in our time. Rabbeinu Asher (otherwise known as the Rosh) writes that the mitzvah of writing a sefer Torah applied in the time when people actually studied from the Sefer Torah. When the Oral torah was already "stored" in their head and the actual reading from a sefer Torah with all the adornments on the letters were meaningful to the reader and subject to discussion. However, as generations went by, with the writing of scrolls from which people started studying and in latter generations with the advent of printing all of our Torah learning is done from printed books. Therefore, using a sefer torah for study is deemed even somewhat disrespectful. However, some explain the Rosh that he did not mean to say there is no more mitzvah for each person to write a sefer for how can we do away with a Mitzvah.? His intention was, therefore, according to this opinion is that we have an additional Mitzvah of printing and purchasing new sefarim such as chumasim, Mishna, Geamrotm and their commentaries. In other words, filling your home with sefarim to learn from is a Mitzvah. Both opinions are brought in the Shulchan Aruch. (See Shulchan Aruch Yoreh De'eah 270 and commentaries.) Form, the practical point of view if we were to follow the opinion that we actually want to write a sefer Torah and not rely upon the opinion that the Mitzvah no longer applies, how can we go about it? It will take quite a long time for each of us to become a qualified sofer and it take quite a while to write a sefer Torah. From that respect, one may hire a sofer to write a sefer Torah for him or even purchase a sefer torah and then have the sofer make corrections and it is considered as if he wrote the Sefer Torah. After that we have the consideration of cost . Can one fulfill the mitzvah of writing a sefer torah by partnership with others? The Pitchei Tshuva ( Yoreh De'eah 270:1, Aruch Hashulchan 270:11)) bring opinions that one does not fulfill the mitzvah since the Torah writes "and you shall write sefer Torah" emphasizing "you" as in the case of Etrog, that each one must have is own. On the other hand, many other Rabbis say that one fulfills the mitzvah through partnership with others. (באר יצחק, סי' יט,שו"ת עמק יהושע סי' יא, שו,ת חסד לאברהם סי' פד ) This is also the opinion of Rav Moshe Feinsein zt'l (אגרות משה יו"ד ח"א, קסג), this is also the opinion of Rabbi Vozner shlit"a Ovadia Yoseph shlit"a (See שו"ת שבט הלוי ח"ג סי' קמז, שו"ת יביע אומר יור"ד ח"י סי' כט) that one may fulfill the mitzvah in this fashion.