Sir/Madam,
I only have an intel hd 4600 integrated graphics card. Would it work? Shall i purchase the licence ?
That’s below our requirements but we’ve had success running on similar specs as that. I’m not advocating you should buy it based on my previous statement though. 
I would recommend upgrading your system. If you’re really eager, you could subscribe and if it doesn’t run, just cancel your account.
SYSTEM REQUIREMENTS:
Desktop PC or Mac
Windows 7 64-bit or Mac OS X 10.9.2 or later
Quad-core Intel or AMD processor, 2.5 GHz or faster
NVIDIA GeForce 470 GTX or AMD Radeon 6870 HD series card or higher
8 GB RAM
I have radeon 5770 and my average fps both in editor and game is somewhere around 20. I don’t think intel’s gpu is a lot more powerful than 5770 so if you should decide if you are comfortable with this or not.
If you buy it, install, and find out it doesn’t run, just contact us for a refund and we should be able to take care of it for you.
how big is the file size?
It works, I’m using it right now. The editor works between 9 and 12fps but game are much smoother.
You can improve the editor performance significantly by switching the view mode to ‘unlit’. In the top left of the view window, click on the button with shaded cube that says ‘lit’, and change it to ‘unlit’.
thanks for the answer.
Or you can just go to “quick settings” and lower your editor’s graphics settings…
edit: oops, this is an aswer for mungobob’s message, hit the wrong button.