Best pass to take to travel in HK

As you are traveling to and from airport, Airprot Express TRavel Pass which contains two Airprot Express rides are recommended. It can also be used to travel on most metro lines for free for three days. The fare is HKD 300. You can also top it up to use it on buses and on remaining days.

Thank you but the only issue is we are there for 4 days so we need on day we arrive and then on the 4th day back from hotel to airport will this be covered will I buy for 300 ?

Only the internal travels on the 4th I will have to reload isn't it or will have to again pay extra for hotel to airport since the three day period wud be over ?

The airport rides will be valid for 14 days. So no worry, you can still use on on the 4th day back to aiport.
The metro rides will be valid for three days, or more specifically 72 hours. To use it to take the metro on 4th day, you will need to reload it.