Where should be the keywords placed in the page?

Title,meta description,meta keywords,content,header tag..

Keywords are placed in page title,page description,page URL.In paragraph sentence,you can also place keywords on paragraph.In paragraph,first sentence and paragraph body.

you can place your keywords in title,meta keywords and in body section of page.

Page title, page url and description, in the shape of paragraph.

You should place keywords in title tag, meta description, meta keywords, content, url & use keywords to describe images. Give alt tag to all images. It will help you get rank better in search engine.

You can place keyword on your title.

You can place your keyword in Title tag, description and keyword tag. You can also put keywords in website content too.