While there are different reasons to take a DNA test, one reason is to find unknown relatives. If you have taken a genetic genealogy oriented DNA test you are probably interested in determining your genealogical link to people you match. When you add a family tree at either the DNA testing company, FamilyTree DNA, MyHeritage, LivingDNA, or AncestryDNA, etc., or at a genealogical website which you link your DNA results to, GENI, WIKITREE, TribalPages, etc., please be as complete with the data for deceased individuals as you can. This means that you include locations, at least county and state in the USA, and full dates of birth, marriage, and death, as far as you know them.
Please don't list deceased persons as Private unless you don't want genealogical relations to find you. In the USA the most recent public population census is that for 1940. The 1950 census will be available in 2022. Having locations and dates allows the person looking at your family tree to make connections with people in their tree to allow identification of the most recent common ancestor/s, (MRCA). This will greatly enhance the possibility of extending your genealogy research.
My suggested minimum family tree would go back to your Great Grandparents with their spouses and children, and work forward and stop at living people on each line. Ideally going back to before the 1850 census would probably work for most people in the USA.
If your ancestry in the 1800s or 1900s was mostly in Europe or otherwise outside of the USA, testing at MyHeritage and/or AncestryDNA will probably be of most use to you. For genealogical records I also suggest using FamilySearch.org due to its worldwide coverage.
I hope this will help you find your relatives.