The default directory for a gurobi.lic license key file is:
You can also put the gurobi.lic license key file into your home directory, though the license will only be available for your account on the computer.
It is easiest if you put your gurobi.lic license key file into a default directory. However, if it is necessary to put the file into another directory, then set the environment variable GRB_LICENSE_FILE to point to the exact location of the file. For example, if the license file gurobi.lic is in the directory D:\work, then set GRB_LICENSE_FILE to D:\work\gurobi.lic. For more information, see the section "How to Obtain and Install a Gurobi License" in the Quick Start Guide.