Free Family Tree
There are many places where you can find family trees for free, but please be discriminating when you use them. Anyone can submit an online family tree on some of the family history sites, or write the information down on paper (and even publish it), without someone scrutinizing it for errors or truthfulness.
Many genealogy web sites (such as OneGreatFamily, Ancestry, and Footnote) allow you to submit or access family trees, but not always for free. You may have better luck finding a free family tree by using a search engine such as Google and entering an ancestor's name. Unless detailed dates and places are given, you will want to be skeptical of the value of the information. In that case, don't discount the free family tree entirely but do use caution and perhaps use it as a sort of "road map" of where to go to document the dates, places and relationships.
The same holds true for published free family trees which you may find in libraries, online or among home sources. They may be in book form or may be a collection of family group sheets and pedigree charts. Find out, if possible, who produced the family tree. See if there is any documentation for the information given.
Family trees can take the form of a literal tree, with an ancestral couple as the trunk, their children forming the main branches, and subsequent generations providing the smaller branches. One of the problems with this form, and with any other visual drawing, is the difficulty in tracing relationships between cousins of varying degrees and sometimes even siblings.
You may have seen the circular type of family tree with the ancestral couple in the middle, their children in a circle around them, grandchildren in a circle around them, and subsequent great grandchildren in yet another circle. It is akin to dropping a pebble in a pond, with each wave representing a generation. I find this particular form of free family tree frustrating because the size of the circle is set, whether a couple is childless or has 18 children.
Family trees can also take the "descending" or "ascending" approach. In the first case, the tree starts with the ancestral couple, followed by their children, then their grandchildren and so forth. This form usually descends from top to bottom of the page. The ascending family tree starts with the author of the tree then includes information on his or her parents, grandparents, great grandparents etc. This form starts at the bottom of the page and works up, although the Personal Ancestral File program, which allows you to enter information on your family tree free of charge, goes from left to right.
I frequently hear someone claim that they have their family tree back to Adam, and I respectively disagree with that possibility. Usually they say they have tied into some royal European line. All sorts of red flags should fly up at that statement. While many of these family trees are free to the public, they are notoriously incorrect. In order to prove his claim to the throne, a monarch would hire a genealogist to come up with a royal line and, if that genealogist wanted to keep his head on his shoulders, he would do just that. I have heard that the Esterhazy family claims to have their line back to Adam's grandfather! In reality, there are no documentary sources to prove anything back before written histories. Even if one was able to get their family tree back into the Bible (a secondary source), there are no connecting family lines back to Adam, let along his grandfather.
In order to document and perform temple ordinances for those who lived before the 1500s, the Church of Jesus Christ of Latter-day Saints requests that all these early submissions be cleared by one of their departments. They have almost a complete collection of documents listing people who lived during that time, and know that temple work has been done for them already.
In summary, the old adage "You get what you pay for" may hold true for free family trees too! Use them with caution, and document the information you find there.