Windows
The default location for installed runtimes is C:\Program Files\MATLAB\MATLAB Runtime. If it is installed in a non-default location, you may be able to find it listed in the list of installed programs in Control Panel.
macOS
The default location for installed runtimes is /Applications/MATLAB/MATLAB_Runtime. If you believe it is installed elsewhere, consider speaking with the person who installed it or search your system for a file named "matlabruntime_license_agreement.pdf" to locate where it is installed.
Linux
The default location for installed runtimes is /usr/local/MATLAB/MATLAB_Runtime. If you believe it is installed elsewhere, consider speaking with the person who installed it or search your system for a file named "matlabruntime_license_agreement.pdf" to locate where it is installed.