There are a number of different Meta tags that you can use, but the most important ones are the Description and the Keywords Meta tags as well as having a title for the web page.
Title (Title Tag)
The title of your web page should also be in the document head and is the most important ‘non-content part of your page as it carries the most weighting with search engines. You should keep this below 60 characters and include your most important keywords first, if you have a company or brand name then it is often better to palace this at the end after your most important keywords for the page.
Page titles can be cut off in the SERPs if they are too long. Page title length is based on pixels shown in the SERPs. Although search engines will read the full title regardless of length, users will only see up until a certain threshold in search results. Google’s threshold is 512 pixels, which equates to anywhere from 50-60 characters depending on the characters used.
Using strong and descriptive keywords is critical to the success of a page title. In general, using 1-3 primary keywords or keyword phrases in a page title is a good rule of thumb. These keywords should reflect the main topic of the page and accurately tell a user what they can expect to find.
Description (Meta Description)
This tag is often used by search engines for the description of your web page. It will not affect the ranking or indexing of your web page, so think of it as an advert for your page and write your description as a short ad of under 160 characters to encourage people to view your page.
Keywords (Meta Tags)
To help get your website up in the ratings you can supplement the title and description with a list of keywords, separated by commas, that someone might type into a search engine when looking for a site like yours. Google will ignore keywords meta tags, but other search engines do use this to help index your website.