In order to copy a file from a running container to your host you first need to get your Docker container ID, you can do that with the following command:

docker ps

Then once you have your container ID, you can run the following:

docker cp container_id:/path/to/your_file.txt /path/on/your/host

Make sure to update the path to the file inside the container and the path on your host where you want to store the file.

You can also use the container name rather than the container ID.

Here is also a quick video on how to do that as well:

Hope that this helps!
Regards,
Bobby