We currently do not have any type of export or download function available anywhere on the Sleeper app.
This is something we hope to offer in the future, but for now, the only way to get any data is to use our public API.
You can view our doc about the API here:
https://docs.sleeper.app/#players
You can get the Players API here:
https://api.sleeper.app/v1/players/nfl