Hey @Ralle82,
If you add an item using the Add new item(+) option in Enpass, there's already a drop down menu to choose the vault where you wish to save the item. Additionally, on desktops, as a part of the auto-save feature, the Enpass extension provides an option to select the vault in which user wishes to save a login item if that's already not in the Enpass database.
If we've missed something, please let us know.
Thanks.