You can donate some decorations for use in your guild Stronghold or Flagship. There are two ways to do this.
You can donate Bind on Use (BoU) decorations to your guild. You must have permission to add items to the Guild Bank and there must be a slot open.
With the item in your inventory (do NOT add it to your own decorations by right clicking on it), open your Guild Bank.
Click on “Decoration Donation” on the lower left side.
Drag the item you want to donate into the box and a pop up will appear.
Click “Yes” and the item will be available for use in your Guild Stronghold or Flagship.