How can I remove Search for product, About us, Log in, etc. which are displayed in Google Search?
And how can I add particular categories like Automobiles, Mobiles & Tablets, etc.?
In order to remove particular categories in the Sitelinks result:
Likewise give all your links to remove from Sitelinks.
You can't add any particular categories manually to get that in Google Sitelinks results and Google automatically consider those links. In order to know more about how to get Sitelinks in Google see What are the most important things I need to do to encourage Google Sitelinks?.
Go to your Google Webmaster Tools account. On left navigation under Search Appearance click on Sitelinks and remove the links you don't want to appear under search results.
Sitelinks are automatically generated links that may appear under your site's search results. Learn more. If you don't want a page to appear as a sitelink, you can demote it. Only site owners and users with full permissions can demote sitelinks.