At a minimum, Vivado implementation requires a synthesized netlist. A design can start from a synthesized netlist, or from RTL source files.
Important: If you start from RTL sources, you must first run Vivado synthesis before implementation can begin. The Vivado IDE manages this automatically if you attempt to run implementation on an un-synthesized design. The tools allow you to run synthesis first.
For information on running Vivado synthesis, see the Vivado Design Suite User Guide: Synthesis (UG901).