I was partner at a couple of hedge funds. Every fund has its own docs, but normally it is going to restrict you to sending money to specific things, you can't just do anything you want. Certainly you cannot just lend it to yourself if you want serious investors, they do a whole due diligence questionnaire about what sign-off is needed, who can sign, audits, and so on.

I remember a friend with a fund, he was in a short-term pickle waiting for some money to bridge a house purchase. Didn't even cross his mind to lend it to himself and pay it back two weeks later, even though that would have been nearly risk free and a minuscule proportion of the fund.