In QloApps when a customer makes a search he selects the check-in and check-out date which cannot be past dates.
So if a person wants to book a room for a single day then he selects the check-in date for the date and check-out date as the next date.
And this way a room can be booked for a single day.
But as I can understand you want only check-in date in the search panel and the customer can make the booking for that perticular date only.
So for this requirement of yours, we will need to customize QloApps. And it will be a Paid Service.
If you want to do this customization your self then you can obviously do it as QloApps is open source and the source code is provided to you.
But any issue or bug arises in the system due to your changes then it will not be our responsibility.