I have searched here for an answer to this basic question and couldn’t find one … so if it has already been answered I apologize.
Scenario: I have two MACs, my iMac and my MBP. They sync DT. (I will ask about iOS at the end).
If I import a folder on my iMac into DT, I assume that the folder gets sync’d over to the MBP (meaning that the files in the folder are actually copied over to the MBP and look like they have been imported there. Is that the case?
The thing that I don’t understand: If I index a folder on my iMac, what happens on my MBP? Is the whole folder (which is large) copied over to the MBP? If so, does it appear indexed there or imported?
I will stop there and ask about DTTG after I understand what happens between my Macs 
If I import a folder on my iMac into DT, I assume that the folder gets sync’d over to the MBP (meaning that the files in the folder are actually copied over to the MBP and look like they have been imported there. Is that the case?
Sync is a mirroring sync so the databases will be the same on each device.
The thing that I don’t understand: If I index a folder on my iMac, what happens on my MBP? Is the whole folder (which is large) copied over to the MBP? If so, does it appear indexed there or imported?
Again, since sync is a mirroring sync, the items would be indexed on the second machine.
Yes, the items would be synced to the new machine but in the same relative location, if possible. For example, if you indexed a folder on the desktop of machine A, sync would create a similar folder on the desktop of machine B and its database would be pointing to those files, not the files on machie A’s desktop.
If you were indexing files in a commonly accessible location, like a Dropbox folder connected to both machines, there is an option to not synchronize the contents of indexed items… BUT you should not use this if you are syncing with DEVONthink To Go as it would have no access to download the contents of files.
Ah. I see. So in both cases the files would appear on the other system, but they would be imported or indexed on the other system based on what I did on the primary system.
That makes sense. Thanks
So, now, what happens with DTTG. Do the files also end up on my iphone?
Yes, but DEVONthink To Go does not support indexing. So while a file may be indexed on the Mac and DEVONthink To Go can sync databases with indexed items, it will always have a local copy of the file.