The typically refers to a modified version of communication apps that provide virtual phone numbers for calls and SMS . Users often seek these "mods" to bypass subscription fees or credit limits required to maintain secondary phone lines.
Some "Unlimited Credit" APKs are actually Trojans. They may look like a Virtual SIM app, but they run background processes that use your device as part of a botnet, clicking ads in the background or mining cryptocurrency without your knowledge, draining your battery and overheating your phone. Virtual Sim Mod Apk Unlimited Credits