Pocket Informant saves events to the calendar you have chosen, and that calendar's source determines what it syncs to. If you are using iOS events, make sure the calendar for your new events is an iOS Calendar.

If you are syncing to Google, make sure the calendar for your new event is a Calendar that syncs to Google.

To set your default calendar please go into the Informant settings, calendars templates, manage calendars and tap the calendar you wish to make the default and set the default option.