Google-style SEO: how do I make it work with my WordPress site?

Google recommends html coding including metanames (in the <head> section) for establishing search parameters for SEO, but when I type in the code using the Text option, Wordpress does not retain the code (as shown when I go to Visual mode). How do I include SEO search words in my WordPress site,, which is a paid membership site using Membership 2 plugin?