You can export your game as HTML 5, then just copy the folder (making sure to include the Index.html file) zip it up and send it to your friend. It should work fine. Just open index.html and you can play the game.
For licensing you need to read the licensing info article. I would highly recomend reading the manual and the tutorials as 99% of your questions will be answered there. Here is the link to the licensing info:
scirra.com/tutorials/57/how-construct-2-licenses-work
FAQ
Which license do I need?
If the license will be used inside a for-profit organisation you will need the Business Edition license.
If you are an individual not affiliated with a commercial organisation you only need the Personal Edition license.
If however as an individual you make more than $5000 USD in revenue from your Construct 2 creations you will need to upgrade to a Business Edition license. Read more about how license with Construct 2 work.
How do I order it as a gift?
Once payment has been received, you will be emailed a key which can be redeemed on our website. If you wish to gift the license, simply give the key to the lucky recipient who can then claim the license from our website.
Do you offer educational discounts?
All educational insitutions are welcome to use the Free Edition! If an educational institution wishes to order more than 10 copies with all the features unlocked please contact us for a quote.
Do you offer discounts for students?
Unfortunately at this time we do not offer student discounts.
How do I order more than 1 license?
Simply add the number of licenses you require to your basket. Once payment has been received you will receive an email with redeemable keys. Once you redeem a key, you will be able to enter the details for each license.