“Meta tags” are used for search engine optimization. The most common ones are the meta description and meta keywords.
- Meta Description:
- Use to provide a concise explanation of the contents of the web page. Meta descriptions are commonly used on search engine result pages (SERPs) to display preview snippets for a given page.
- Optimal Length for Search Engines: Roughly 155 Characters
- Meta Keywords:
- Use to provide a brief and concise list of the most important themes of your page
- Meta keywords tags should adhere to the following guidelines: (1) keep your list of keywords or keyword phrases down to 10 - 15 unique words or phrases; (2) separate the words or phrases using a comma (you do not need to leave a space between words separated by commas); (3) do not repeat words or phrases; (4) put your most important word or phrases at the beginning of your list.
- There is no official length requirement but generally you'll see people mention anywhere from 100 to 255 characters
Preventing Google & Bing from indexing a Published Page
To set a noindex rule, expand the advanced tags section under Meta tags. Under robots, check the respective "prevent" checkboxes. See screenshot below: