A range of virtualization software; VMware Fusion is the name of the product for macOS. For questions about VMware products unrelated to macOS, please consider Super User.
VMware Fusion is a virtual machine software product developed by VMware for Macintosh computers with Intel processors. Fusion allows Intel-based Macs to run x86 and x86-64 "guest" operating systems, such as Microsoft Windows, Linux, NetWare and Solaris as virtual machines simultaneously with Mac OS X as the "host" operating system using a combination of paravirtualization, emulation and dynamic recompilation.
If your question is about VMware but not related to macOS, it's off-topic here; consider asking your question on our sister site Super User.