On Sunday,  4 Mar 2018 at 23:22, Shérab wrote:
> I would like to add an item with the
> corresponding date to my agenda file. What would be the most direct /
> straightforward / idiomatic way to achieve this, please?

try "i d".  "i" should be bound to org-agenda-diary-entry.  This is the
route I use for adding entries to my agenda all the time.

-- 
Eric S Fraga via Emacs 27.0.50, Org release_9.1.6-191-g90607d