What is This tool?
It is a free meta data generator that you can use to create structured information about your webpage(s). The tool covers the most widely used tags by search engines such as the robots and meta description tags.
This meta generator also features options for Facebook Open Graph and Twitter Card metadata as well as DNS prefetch and the ability to add as many custom meta tags as you wish.
Once you are done copy the outputted code and paste it into the <head></head> section of your HTML.
Just as a side note it is worth checking out Google's tips on how to create good titles and snippets in search results and my Google SERP snippet optimization tool to get the best representation of your page in search.
Hopefully, you find this tool useful. If you would like it to be improved in any way please let me know in the comments.