Now I can use GMail, but the problem is that Google docs system is not available in Yahoo, but my main eMail is registered with Yahoo.
You can add a filter in yahoo options to forward all mails to your gmail account... that way you won't have to care about your yahoo inbox, when all the mails would be forwarded to your gmail which can then be set as primary...
What's eMail ?? I think you meant just email or EMAIL... don't know why it's eMail....??
From what I can see - you can only enable POP in Yahoo Mail if you upgrade to Yahoo Plus - and the same goes for forwarding your emails to another inbox. Take a look at these two methods to avoid having to upgrade
The article is a year old so the methods might not work anymore but they're worth giving a try.
you can use POP3 to read your Yahoo eMails in GMail. You can also set up GMail in a way that allows you to send eMail from GMail using the Yahoo SMTP, i.e. the recipient will think the mail was sent from Yahoo.
Follow this tutorial to get started:
Then refer to this tutorial, to set up the custom 'from' address, i.e. your Yahoo eMail address: