There are a few threads on reddit about it. The following is from someone who managed to make an account:
https://www.reddit.com/r/Bitcoin/comments/7t5bk9/initial_thoughts_on_robinhood_crypto/He had the following to say:
As things stand with Robinhood basic/free accounts now, HODLers like myself are not able to send coins offsite either as a means of payment or, in my case, to my Trezor for cold storage. You may apply for Robinhood Gold status to send coins offsite (couldn’t find anything in the documentation showing this, Segwit/no Segwit, etc., but I just just got the account and am still digging). Robinhood Gold accounts have a monthly maintenance fee, which would act as a drag on my returns as a HODLer. The fees are not obnoxious, but not the route I want to go just to be able to send coins. As their user base expands and they get more skilled at servicing client needs, I hope they will include this ability in their free/basic accounts.
