CLI / Command Line Interface
Firefly III has a few commands you can use. See this reference to a list of commands.
Docker
Run the following command on your command line, and replace COMMAND:COMMAND with the actual command from the list below.
docker exec -it $(docker container ls -a -f name=firefly --format="{{.ID}}") php artisan COMMAND:COMMAND
If this doesn't work, replace the $(..) part with your actual Docker container ID:
Self-managed
Run:
Third-party
Most third party systems, like Heroku, don't allow you to do this.