VMware is a virtualization program that allow you to run virtual OS in your computer, in other words, if you want to run a program that only works on Windows XP or Linux, with this program you can do it without leaving your current OS.
Recently Broadcom bought VMware and it seems is going to another direction with the company, but made current versions free for personal use.
To download the program you need to register in their website, I suggest to use a secondary email just in case they begin to send emails for their new products.
Remember download the version VMware Workstation Pro 17 for personal use, (HERE) once you registered and being logged in their website.
Also there is a Apple Mac version called VMware Fusion Pro, you can download it (HERE)
VMware is main program for run virtual machines in your computer, is used almost in all big companies, not sure about their future, but could see a subscription based model with Broadcom soon, not sure how much time this software will be free.