This is the approved revision of this page, as well as being the most recent.
Three handmade Matzahs
How to make the Brachot
One should take the Matzahs, the whole one on bottom, the broken one in middle, and another whole one on top, and make the Bracha of HaMotzei. Then one should drop the bottom matzah which is whole and make the Bracha of Al Achilat Matzah. 
Then one should break off a piece from the top and middle Matzahs to have a Kezayit from each.  The best way to do that is to eat both pieces simultaneously. If one is not able to eat both together, one should eat the piece from the top Matza first 
For someone who can't eat the appropriate amount of Matzah according to Ashkenazim, should have at least 17 cc (which is 9 rows on a machine matzah). 
For someone who it’s difficult to eat that much Matzah one may dip the matzah in water for a second and then eat it. 
Matzah soaked in water is fit to exempt one's obligation after the fact. Some say that if the matzah is soaked any liquid other than water it is invalid for matzah mitzvah, while others disagree.
How to eat it
Since our Matzahs are thin and hard to eat 2 Kezayitim in Kedi Achilat Pras one should eat then one after another. 
Ownership over the Matzah
The minhag is that one doesn’t need to acquire the Matzahs from the homeowner, however, the pious maintain this practice. 
Some say that even for Ashkenazim it's permissible to have soft Matzahs and for those that it's difficult to eat hard matzah it's preferable to eat Soft Matzah. 
Many poskim permit eating machine matzah to fulfill the mitzvah of eating Matzah at the seders, if the matzah was made with intent to be used for the mitzvah of Matzah. 
There’s no difference in preference in having whole wheat or white flour matzah. 
Sephardim hold that one should have hand baked matzah for the seder.
One should certainly buy matzot baked before Pesach and not on Pesach itself.
According to Ashkenazim one should not eat egg matzah on Pesach unless one is ill or weak. However, according to Sephardim it's permissible to eat but one can not eat it for the mitzvah of Matzah at the Seder, however it's praiseworthy to avoid it. 
↑S”A 475:1, Mishna Brurah 475:2. Mishna Brurah (475:2) explains that the reason we take three matzot for hamotzei is because we are trying to satisfy two different approaches. The two whole matzot serve as lechem mishneh, the requirement of having two whole loaves of bread on Shabbat or Yom Tov. The third matzah, or the broken piece of matzah, represents the poor man who does not have a complete piece of matzah. In developing this further, the Shulchan Arukh HaRav (475:4-5) explains that for al akhilat matzah one should place the bottom matzah down since al akhilat matzah applies to the top matzah or the middle broken piece.
↑S”A 475:1. Mishna Brurah (475:9) explains that one needs to eat a k'zayit from both the whole matzah as well as the broken one because some argue that the berakhah of al akhilat matzah applies to each of these matzot. Accordingly, Rav Shlomo Zalman Auerbach (Halichot Shlomoh ch. 9, n. 40) writes that if the three matzot that the head of the household is using does not suffice for everyone to have two kezaytim, each person should just have a piece from the top matzah and then supplement it by eating other available matzah up to the necessary k'zayit. He explained that according to Mishna Brurah, if one isn’t eating from the head of the household’s matzot, there exists no doubt as to which matzah the berakhah of al akhilat matzah applies. Alternatively, Rav Hershel Schachter (Eretz HaTzvi p. 40-1) explains that the reason to require two kezaytim of matzah is to satisfy a) the mitzvah of matzah, b) the mitzvah of seudat yom tov.
↑Halichot Shlomo (pg 282 note 274), Chaye Adam 129:2
↑Magen Avraham 461:7 writes that if the matzah was soaked in any juice or tasty liquid it would invalidate the matzah since it would give it a taste and the matzah needs to taste like matzah (Brachot 38b). However, Rav Chaim Soloveitchik in his notes on Pesachim 41a disagreed. He held that if the matzah had a taste it is still considered matzah mitzvah as long as it wasn't cooked. Nonetheless, in order to have the taste of the matzah linger in one's mouth at the end of the night one would need to eat a bit of non-soaked matzah afterwards.
↑ Rav Hershel Schachter YUTorah.org between minutes 58 and 66. Rav Shlomo Zalman Auerbach in Halichot Shlomo 9:80 says although in the past ashkenazim may have eaten it there is no tradition anymore to permit it. Rav Asher Weiss at the end of the Minchat Asher Haggada siman 15 writes that really it is permissible but there may be some concern that since we aren't experts in making them soft it may become chametz.
↑ Rav Schachter on OU Pre-Pesach Webcast 5770 between minutes 75:15 and 81:00. In a shiur on yutorah.org, Rav Schachter discussed the issues of Machine Matzah at length. The major issue was whether the pressing of the button to start the machine is considered enough of an action of a person to consider the matzah to be baked lishma. He concluded that it many poskim consider it to be acceptable Shemurah Matzah. He also quotes Rav Soloveitchik saying that he found machine matzot to be preferable for the mitzvah of eating matzah at the seder. Bikvei Hatzoan he shows this point from the Gra YD 3. (See Maharsham 2:16 who quotes those who are lenient.) Haggadah of the Roshei Yeshivah (pg 2) records the practice of Rav Isser Zalman Meltzer to eat machine matzah for the seder. See Hakira v. 25 p. 31 fnt. 57 quotes that Rav Moshe Soloveitchik held that machine matzah was as good if not better than hand made matzah and he would give it to his children for the seder, though he himself had hand made matzah for the seder. He explained that there's no minhag to eat hand made matzah since you can't have a minhag that isn't based on any halachic factor.
↑Yacheve Daat 1:14 writes that since it is a major dispute if the Jew who presses the button to bake the matzot is considered lishma one should avoid the question for the mitzvah deoritta of matzah. Yalkut Yosef 475:32 concurs. See Yabia Omer YD 4:20:9 who references this idea as well.
↑Tur end of OC 458 writes that one should bake one's matzot before pesach in case there's any crumbs of chametz mixed in they would be nullified and permitted on Pesach. He is in line with his own opinion in Tur OC 447 that once chametz is nullified in food before pesach it remains nullified. Yabia Omer O.C. 2:23 applies this to machine matzot that might have a crumb of chametz mixed in but was nullified before pesach. He shows that the minhag is like the opinion of Shulchan Aruch that there's no chozer vneer by chametz before pesach.
↑Daily Halacha by Rabbi Mansour. Kitzur Shulchan Aruch 117:6 writes that the elderly and sick may eat Matzah Ashirah which is made from fruit juice, eggs, milk, or wine as long as no water was added. However, if there's not such a great need one shouldn't bake Matzah Ashirah.