Object: 

Objects are nothing but tables within the regular database. Any data stored within the salesforce is going to be saved to things. There are two types of objects they were Standard Objects and Custom Objects.

Standard Objects:  Objects which are created by the salesforce or default objects in salesforce are called standard objects. Examples are Account,Contact,User,Profile ,UserRole,Lead,Opportunity. They cannot be deleted but they can be customized .

Custom Objects:These are the objects created by user to meet his organizational business requirement. All the custom objects are appended with __C 

Ex : Customer__c , Loan__c ,Payment__c .

Steps to create Custom Objects:

Classic:

1.Click on Setup

2.Click on Build

3.Click on Create

4.Click on Objects

5.Click on New Custom Objects

Lightning:

1.Click on Setup

2.Click on Platform tools

3.Click on Objects and Fields

4.Click on Create New Object

5.Enter Object Label for example: customer, Objects are  displayed on the User Interface with object Label.

6.Enter Plural label For example: customers, If we create a tab for this object , the label that should be displayed on the tab is called plural Label.

7.Enter Object Name for Example : Customer, If you want to refer to object Programatically we use object Name.

8.Context sensitive help: On Every object salesforce provides help for this page Link. When we click on the link which document should be opened is defined using these settings. Open the standard Salesforce.com Help and Training window. If this option is selected, a salesforce standard document will be opened. Open a window using a Visualforce page. If we choose this option we can create our own visualforce page as a help document.

9.Record Name Label and DataType: Salesforce by default on every custom object creates one standard field with name ” Name”. With what label this field should be displayed on the ui is defined as Record Name Label. This is a required field. This will accept only Text and AutoNumber as datatype. If we choose the data type as Text, This will accept alphanumeric data and the user has to manually enter the data. If we choose the data Type as Autonumber, Then system will generate the data based on the format that we have given.

Ex :

         Format  : REGD NO{0000}

         Start      : 0

         REGDNO0001

         REGDNO0002

         REGDNO0003

         Format : OR-{000}

         Start     : 501

         OR-501

         OR-502

         Format : {mm}{dd}{000}

         Start      :1

         1029001

         1029002

10.Optional Features: These options can be enabled or disabled at any stage of the application.

Allow Reports: If you enable this option ,we can create reports on the data which is available in the object.

Allow Activities: If you enable this option we can create Events and Tasks on this object.

Track Field History: If you enable this option we can track the changes made on the fields of this object.

Allow in chatter Group: If you enable this option we can create chatter groups on this object.  

11.Object Classification:

a. Allow Sharing

b. Allow Bulk API Access

c. Allow Streaming API Access

If we enable all the  three options then it is an Enterprise Application object.If we disable any one of this option we call it a Lightning application object.

12.Deployment Status: 

In Development: If we enable this option  only the Administrator will be able to access this object, no other user can see this object.

Deployed: If we enable this option, All the users in the organization can access this object based on the security model of the organization.

13.Allow Search: If we enable this option content of this object can be searched from global search.

14.Object Creation Option: These options can be enabled or disabled only at the time of creating an object. Add or include Notes and Attachments related list to default page layout. Launch New Custom Tab Wizard after saving this traditional custom object.   

Schema Builder:

We can also build custom objects using Schema builder.

Steps to create objects using schema builder:

1.Click on Setup

2.Click on Build

3.Click on Develop

4.Click on Lightning Bolt

5.Click on Schema Builder

6.Click on Elements

7.Click on the Drag and drop object icon.