This setting is intended to limit the time in which SMS messages can be sent by a manager / trigger or during bulk mailings. If you select "Yes" in the *"Limit sending time" *field, an area will open where you enter the range of time in which SMS messages are allowed to be sent.
For example, if you select from 09:00 to 20:00, and the SMS is sent by a manager or trigger at 21:50, then the message will be added to the queue and will be sent at 09:00 the next day.
Please note that this setting takes into account the customer's time zone.