Access files on an iMac from a MacBook

While it is actually asleep you cannot.

However, if you have a Bonjour Sleep Proxy server on the network with your iMac, then it may be possible

<https://en.wikipedia.org/wiki/Bonjour_Sleep_Proxy>

A Bonjour Sleep Proxy server will listen for connection requests to your iMac, and when it sees them, it will send a Wake For Network Access magic Wake-on-LAN packet to the networking hardware on the iMac, which should cause it to wake up. This assumes the iMac has System Preferences -> Energy Saver -> Wake for network access enable.

This should always work if the iMac is connected via ethernet, or if your iMac has a WiFi chip that supports Wake-on-LAN networking packet, then the iMac can be on WiFi.

But first you need a Bonjour Sleep Proxy Server on the LAN with your iMac.

Or you could use iCloud documents and desktop or another cloud service to synchronize your documents between the two machines.