Moyes is leaving Everton to replace Ferguson, who is retiring after 26 years at the helm at Old Trafford.
Ferguson said: “I think the enormity of the club – he will soon realise that anyways. The global brand and number of sponsors we have here, he has to fit into that. I don’t think that’s an issue, though, and the most important thing is the team.
“He’s got a good squad of players and he will want to add to that, I’m sure, himself. He will have his own ideas and that’s good. He will be fine.”