An IP integrator block design can be integrated into a higher-level design or it can be the highest level in the design hierarchy. To integrate the IP integrator design into a higher-level design, instantiate the block design as a module in the higher-level HDL file.
You can perform a higher-level instantiation of the block design by selecting the block design in the Vivado IDE Sources window and selecting Create HDL Wrapper. This generates a top-level HDL file for the IP integrator sub-system. See this link in the Vivado Design Suite User Guide: Designing IP Subsystems Using IP Integrator (UG994) for more information.