Hi Kavitha,

May I suggest you please double check with below steps which are working absolutely fine for me.

After creating the custom object, you have to expose it as a tab.
Define a new tab to display the data stored in your custom object records.

From Setup, click Create | Tabs.
Click New in the Custom Object Tabs related list.
Select the custom object to display in the custom tab. If you have not already created the custom object, click create a new custom object now and follow the instructions in Define Custom Objects.

The label of the new tab is the same as the plural version of the custom object label.

Click the Tab Style lookup icon to display the Tab Style Selector.

If a tab style is already in use, a number enclosed in brackets [] appears next to the tab style name. Hover your mouse over the style name to view the tabs that use the style. Click Hide styles which are used on other tabs to filter this list.

Click a tab style to select the color scheme and icon for the custom tab. 
Optionally, click Create your own style on the Tab Style Selector dialog if you want to create a custom tab style and your organization has access to the Documents tab. To create your own tab style:

Click the Color Lookup icon to display the color selection dialog and click a color to select it.
Click Insert an Image, select the document folder, and select the image you want to use.
Alternatively, click  Search in Documents, enter a search term, and click Go! to find a document file name that includes your search term.


Specify the custom apps that should include the new tab.
Check Append tab to users' existing personal customizations to add the new tab to your users’ customized display settings if they have customized their personal display.
Click Save. 

To further customize the tab:

Define the page layout for records displayed in the tab. The page layout controls which fields are visible and editable when users are entering data in the custom tab.
Specify which fields display to users in the key lists section of the custom object tab home page.

Please let us know if any further clarification is required.

Hope this helps.

Please mark this as solved if it's resolved so that it gets removed from the unanswered queue which results in helping others who are encountering a similar issue.

Thanks,
Nagendra