Yes, my brother did the Y-DNA & mitochondrial tests, & my husband, one daughter, and I have had the autosomal DNA test. Two of the major testing companies are FamilyTreeDNA & 23 & Me (referring to 23 pairs of human chromosomes).
"Do they really work?" is another question. If you refer to Y-DNA, the person to be tested has to be a male with the correct surname. There are family projects, and comparing others from the same family can prove whether your line is really from DUNHAM aka SINGLETARY.