A virtual machine is a computer inside a computer (or a phone inside a phone). There are more and more virtualization tools and methods available today: from full virtualization of the operating system (e.g. VitrualBox/VMware), to containerized versions that do not create a complete machine, but emulate only some necessary elements for work (e.g. Docker).
The basic principles of virtualization: A special software is installed on the host machine, inside which the virtual machine (guest) is started. There can be one or several virtual machines (depending on the chosen method and software) and the virtual machine runs on the resources of the host system (memory, RAM, CPU, video card). Often, in addition to special software, you also need images of the virtual machine, i.e. a ready-made machine in the assembly, which should be run in the program. Exceptions are programs that already contain an image, but this is a rather limited solution, because it does not allow you to configure the machine properly before launching it.
BespalePhone knows how to virtualize android machines (phone inside the phone). We complete phones at once three different images (builds), for different tasks:
full (google + root + tools to hack games/apps for money/premium)
google (crystal clear build, as if you have bought a new phone in a store and turned it on)
root (empty build with no extra eyes, for delicate tasks)