In this article I am going to explain Content types in SharePoint 2010.
What is Content Type?
- A content type is used to define a SharePoint entity.
- A Content type is a group of site columns (or metadata), workflows and other settings for the item in the list or document in document library or for SharePoint page.
- Content types are reusable component, they are not specific to any list or library or page layout. The base type of a content type could be an existing content type like:
Item
Document
Folder
Event
Task
Message
Comment
Post
Now we will learn how to define Content type and how to use:
Step 1 # Open your SharePoint Site.
Step 2#: Go to Site Action -> Site Settings

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Go to Galleries -> Site content types.

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Click on Create.

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Name: The name of the content type.
Description: Description of content type.
Parent Content Type: Content Types can inherit from existing content types and they are grouped together by a Group Name
i. Parent Content Type from: Select an existing group. Since we are defining a content type that will be used to generate a document we use the 'Document Content Type' group
ii. Parent Content Type: We want the content type to be applied when we are adding a new document to a library in the site.
Group: Select under which group our new content type should be categorized.
OK.

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Now the time to define columns. Here you have 2 options either select site column or create new. We will add column by using both method.
First by using: Add from existing site columns:

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Here select your group from which you want to add column. Click Ok.

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After clicking (Add from new site column) link button a new form will open, here enter your column name and select appropriate properties and click OK. Here I am going to add below columns.
You can see your added columns. Now we will add from new site column. Here I add below column.
1. Employee Name:
a. Column Name: Employee Name
b. Type: Single Line Text
c. Group: Custom Columns
2. Experience:
a. Column Name: Experience
b. Type: Single Line Text
c. Group: Custom Columns
3. Contact Number:
a. Column Name: Contact Number
b. Type: Single Line Text
c. Group: Custom Columns
4. Employee Address
a. Column Name: Employee Address
b. Type: Multiple lines of text
c. Group: Custom Columns

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Now time to use this content type. So add a new document library.

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By clicking on More Options enter Name, Description. Select Navigation, version and Document Template value. Click OK.

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Now select your Document Library -> Select Library -> Select library Settings.

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Select Advance settings here.

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Select (Allow Management of content Types to Yes). -> Click OK.

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Here Select Add from existing site content types.

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Select Group -> Select you content type -> Add -> OK.

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Now you can see all columns here in this document library. Here you cans ee in Content type 2 content types are coming so we will make disable Default content type ie: Document.
Click Change new button order and default content type.

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Unchecked Document Content type to make invisible. -> OK.
Now Time to upload new document -> Select your document library -> click Add document.

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After selecting document click Ok. A popup will come automatically.

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Fill form -> Click Save.

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Here you can see your uploaded document. But you are unable to see all columns. To make visible all columns we need to modify default view -> In library -> Select View -> Modify View

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Select all your columns which you want to show -> and click OK.

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Now you can see your entire column.