Someone else already responded. It's a one-line command.
I never could get poetry to work right; it's configs are sort of messy. pip freeze > requirements is built in. The only thing it doesn't pin is the python version itself.
As explained elsewhere in this thread, the one line command only generates a lock file. This doesn't manage the dependencies so if you want to upgrade cool-lib and recalculate all the transient dependencies so they fit with the rest of your libraries, you cannot afaik.