Right-click Valheim in your Steam library
Select Properties
In the General tab, look for the Launch Options field
In it, type -console
Close the General tab
Once in the game, to activate cheats, open the console by pressing F5. Pressing F5 will close it again as well.

Type devcommands and press enter (previously, the command was 'imacheater' but that has changed). Then you'll be able to use the following cheats in singleplayer mode. They won't work on a multiplayer server.

Also in singleplayer, you can enter debug mode to access a few more cheats and what is essentially a creative mode, where you can build without a workbench or resources.

debugmode - Enters creative mode.



source: https://www.pcgamer.com/valheim-cheats-console-commands/


Hope this helps any!