No. Cells come in two broad structural types: eukaryotic cells, which have a membrane-bound nucleus and other organelles, and prokaryotic cells, which lack those internal membranes and keep their DNA in a nucleoid region instead.
Bacteria and archaea are prokaryotes; animals, plants, fungi, and many protists are eukaryotes. So while eukaryotic cells are common in complex life, they are not the only kind of cell on Earth.
Source: Encyclopaedia Britannica — Eukaryote (updated Sept. 18, 2026); see also Britannica’s Prokaryote overview.