Narita Airport to Tokyo

With Japan Rail Pass is it possible to travel from Narita Airport to Tokyo in free of cost.

Depends where in Tokyo. If you mean Tokyo station, then yes.

Actually I will get down at Narita Airport at 1500 hrs. After activation of Japan Rail Pass we will catch Narita Express upto Tokyo station and then we will board in Taikado Shinkansen for Osaka.
Few days before in this website, there was written that unlimited travel from Narita Express from Airport to Tokyo.
And now it is not mentioned. That's why i was confused. I need Narita Express for round trip.
Thanks

Narita Express rides are fully covered by a Japan Rail Pass; that is mentioned in the article (of this japan-guide.com website) featuring Narita Airport [NRT].
http://www.japan-guide.com/e/e2027.html
I wonder which page(s) of this website you actually checked, but maybe you read this article first then second the article introducing Japan Rail Pass, where its coverage of Narita Express rides is not explicitly mentioned.
http://www.japan-guide.com/e/e2361.html

I need Narita Express for round trip.

When and how long will your travel?
How is your itinerary?
If Osaka City is the furthest place from NRT to visit and you don’t plan another long-distance trip, Japan Rail Pass may not save your cost much.

The Shinkansen station in Osaka City is Shin-Osaka Station; please make sure not to mix it up with Osaka Station.
Each railroad station in NRT has a name with the word "airport"; please note that Narita Station is located outside the airport.

When you reserve a seat in a Narita Express or (Tokaido) Shinkansen train, you get issued a reservation ticket, on which surface the train’s name and number, the section of the ride, the expected departure and arrival time, the car number and the seat number are indicated.
Your plane is scheduled to arrive to NRT by 16:00, so you probably can visit JR East Travel Service Center in NRT Terminal 1 or 2 during the business hours.
http://www.jreast.co.jp/e/customer_support/service_center.html
(Currently there is no railroad station in NRT Terminal 3.)

After a minor change of the rule in March 2015, seat reservation in Narita Express trains has been not always necessary; however, it is recommendable that you reserve your seats, because a passenger using a reserved seat without reservation should yield the seat when a holder of the corresponding reservation ticket appears.

we will catch Narita Express up to Tokyo Station

Shinagawa Station, which is definitely simpler than Tokyo Station, sounds better for you to make a transfer from Narita Express to Tokaido Shinkansen.

A Narita Express train to leave NRT which has two destinations (e.g. Ofuna and Shinjuku) gets divided into two trains in Tokyo Station, one is to make a stop at Shinagawa Station and the other is to skip it.
Any Narita Express train which has only one destination makes a stop at Shinagawa Station.

First of all, Thanks to you omotenashi & sorry for late answering. You had taken lots of pain for me. You explained every thing in detailed. So I am sure, if I ask you any doubt about Japan travel, you will definately helps me.
I am giving you some details about our tour. 20 days before also I was asked some question in this site forum. And I got nice responce. This site is very useful.
We are 6 adults and this is our first trip to Japan.
We are in Japan from 6th Nov 2017 to 12th Nov 2017 for 7 days. For travel, we are purchasing 7 days Japan Rail Pass.
Our itinerary is given below:
Day 1 : Arrival in Narita Airport at 1500 hrs. Then Narita Airport to Sinagawa by Narita Express & Sinagawa to Shin Osaka by Shinkansen. ( As per you suggetion )
Day 2 : Hiroshima & Miyagima & back to Osaka
Day 3 : Osaka Castle & either Himeji Castle or Nara Todaiji Temple
Day 4 : Kyoto
Day 5 : Hakone
Day 6 : Tokyo Local
Day 7 : By Narita Express to Narita Airport for departure to our country, INDIA.
I have doubts about activation & reservation of Japan Rail Pass.
Where can I activate my JR Pass in Narita Airport? And seat reservation for Narita Express & Sinkansen ?
I will travel Shin Osaka to Hiroshima & back, Shin Osaka to Kyoto, Kyoto to Odawara and Odawara to Tokyo by Shinkansen. My doubt is, every time, Is it necessary to reserve seat in departue station before boarding train? And where it will possible? Is there any seperate window for reservation?
Please guide me.
Thanks.

Hello, again.

At a counter of JR East Travel Service Center in NRT Terminal 1 or 2, you can turn in your Exchange Orders for Japan Rail Passes and try to reserve seats in Narita Express and Shinkansen trains.

JR seat reservation can be made from one month before the boarding date, so you can reserve your seats for any N’EX or Shinkansen ride in this 7-day journey as long as there are enough vacant seats.
(You six adult passengers may have seats in some non-adjacent blocks.)

Our itinerary is given below:

Hmm…, it sounds hectic, but I suppose you can do it if you select sites to visit.

Let me suggest some minor changes.

Day 2 [Nov. 7]
: Hiroshima City.
: Miyajima Island, staying there overnight.
Day 3 [Nov. 8]
: Miyajima Island in the early morning.
: Himeji Castle.
: Osaka City in the evening, staying there overnight.
Day 4 [Nov. 9]
: Osaka City in the early morning.
: Nara City.
: Kyoto City in the afternoon, staying there overnight.
Day 5 [Nov. 9]
: Kyoto City.
: Hakone in the afternoon, staying there overnight.
Day 6 [Nov. 10]
: Hakone in the morning.
: Tokyo.

Hello omotenashi,
Thank you very much for your guidance.
I know, our program is little hectic but time & money is main problem.
It is not possible to spend more time in Japan. So we are trying to cover as much as possible.
I will follow your instructions while making reservation. And definately I will consider your suggestion about our program. If I have any problem regarding Japan tour, I will contact you.
Once again thanks.