Verification tasks can be designed during the Planning process of project management. For example, if the project will need clinical trials for design verification then anticipating and formulating them in the Planning process would ease the remainder of the development processes. Also, Verification can be done after Design Input of the Planning process; we can evaluate and verify that all the requirements for the design have been met. In fact, waiting to this during the Validation/Executing process would be both costly in time and money because, if a requirement is missed, a change in the design must be made and we would have to return to Planning and start at its very beginning again. Performing Verification after Design Input would also ferret out any suspicious and incompatible requirements. In the Initiating process Verification can be used to compare the design proposal to similar existing designs and their analyze success. Essentially, Verification used before the Executing process is for establishing a well-founded design. During the Executing process, Verification is more active because tests are performed and analyzed assessing whether or not the device was rightly designed. For this reason, Verification is often thought to be alongside the Executing process of project management. Verification after the Executing process can be used for quality assurance purposes. For example, assessing whether the design packaged right (Closing process) or any extraneous difficulties such as, does the device need to be sterilized or must special disposal procedures be done (Monitoring and Controlling process)? Therefore, Verification is very flexible and can (should) flow into every Process.

References:
https://www.fda.gov/RegulatoryInformation/Guidances/ucm070627.htm#_Toc382720784