Yes. You can transfer the world data files to your friend, Have a look at C:\User\"Your User Name"\Appdata\LocalLow\IronGate\Valheim\worlds_local. Now you just have to transfer your world files to your friend.
If you use the Steam Cloud to save your games, my best guess is to disable that way of saving your world files and then saving them locally (be careful with my Steam Cloud advise here as i avoid saving my games in the Steam Cloud like the plague from ancient times - so i have no plan whatsoever with that Steam Cloud nonsense....).

MFG
CKTMC