imjpmig.exe belongs to the Microsoft Input Method Editor. It is used to simplify the input of Asian characters in the Microsoft Office suite.
It is an essential tool for the proper functioning of the programme and thus should not be removed.
Non-system processes like imjpmig.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that over time your registry suffers fragmentation and accumulates invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues