Having remembered sending them before, I have been investigating.
They appear in the list of things that can be sent by convoy, and assume this is the only way.
Maybe someone else can confirm this, and also, as I have recollecctions about this,it would seem you cannot send them if you are the chief.
In Town View click on the Market, then on Resources aid then on Clan Stronghold send resources. Scrolls are the second item shown and you either move the slider across or type in a number then click send. This initiates a march berween your location and the Stronghold (so you need a march to be free).
The chief can send scrolls, and anything else, to the Stronghold.