"Native American Heritage" means that you are able to document that you are a direct descendant of someone who was an enrolled member of a historical tribe that no longer exists (think descendants of Pocahontas) or who is or was enrolled in/a citizen of a Federally acknowledged modern tribe. Having relatives who are (or were) Native Americans doesn't make you Native American unless you, too, are a citizen of a Federally acknowledged tribe.
Native American ancestry is not determined by pictures, by someone's appearance, by DNA, by family lore, or by participating in powwows or other tribal activities. It's determined by documentation, the same as any other genealogical relationship.
Lots of people are interested in Native Americans for all sorts of reasons. Many thousands of Americans have a family story that includes a long-ago Native person; almost all are unfounded. Anyone with an interest is welcome to work on Wikitree profiles, but there is an added responsibility when working with Native American profiles to be sure you are working from reliable sources, to present documented facts, to strive for historical accuracy, to avoid stereotyping, and as far as is possible to present material in a non-biased, culturally-sensitive manner. All historical figures accumulate myths over time and that seems to be especially true of Native Americans, so often there is a lot of research involved to separate fact from fiction when creating a profile.