(What time is it?)
Wann findet der Vortrag statt?
(When is the presentation going to take place?)
Wer hat das veranlasst?
(Who arranged that?)
(Do you know what time it is?)
Können Sie mir sagen, wann der Vortrag stattfindet?
(Can you tell me when the presentation is going to take place?)
Können Sie mir mitteilen, wer das veranlasst hat?
(Can you let me know who arranged that?)
Indirect yes/no-questions take "ob" ( = if, whether) as a subordinating conjunction.
(Will the goods be dispatched tomorrow?)
(Can you tell me whether the goods will be dispatched tomorrow?)