How to establish voice over ip to use as user

More information would be required to even begin to help with this.
Are you using software VoIP or hardware ?
Error messages or anything else that might help.

Are you looking to establish VoIP in a residence, in a business or what? The more you pout into a question, the better we can answer. With the little you put into this question there is not way for us to help.

Are you looking to establish VoIP in a residence, in a business or what? The more you pout into a question, the better we can answer. With the little you put into this question there is not way for us to help.
I want to establish in home voip please suggest me hardware voip and software both

Well it really depends on where you are, but Skype is a good starter.

You can check out skype.com or vonage.com for services independent of your broadband carrier. Or you can contact your carrier for whatever services they offer.

The services you use will dictate the hardware and/or software you need to use.