What is field set? How can I create a field set in Salesforce?

Hi,

A field set is a grouping of fields. For example, you could have a field set that contains fields describing a user's first name, middle name, last name, and business title. When a field set is added to a Visualforce page, developers can loop over its fields and render them.

Steps to  create and edit field set in salesforce:

1.From the management settings for the appropriate object, go to Field Sets, and then click New.
2.Enter a Field Set Label. This is the name presented to subscribers who install the field through a managed package.
3.Optionally, enter a name for your field set. This is used by your Visualforce page to reference the field set.
4.In the Where is this used? area, provide a brief description of which Visualforce pages use the field set, and for what purpose. This information helps a subscriber understand where and how an installed field set is being used, so that they can populate it with their own fields.
5.Save your changes.
6.To add fields to the field set, drag the fields from the object palette and drop them into the Available for the Field Set or the In the Field Set container. The fields in the Available for the Field Set container are not initially visible on the Visualforce page. The fields in the In the Field Set container are visible by default.You can drag and drop a field from one container to the other. The vertical order of the In the Field Set list indicates the order of how the fields render on Visualforce pages.

7.To remove a field from the field set, drag the element back to the object palette, or click the   icon next to the element.

8.To make a field required, double click the element or click the wrench icon ( ) next to it and select the Required checkbox.

9.Save your change