I have 2 projects, project A and project B, Now this projects are created inside same GCP account. I want to know if there is any option to move instances from project A to project B.
There is no special provision given by GCP to its users to migrate from one project to another. But you can migrate it with the help of a boot disk. But directly there is no such option to migrate instance.
For more details, refer to this tutorial on Google cloud certification.