editing showing only html, not wysiwyg

Hi – I have a new WP blog that was fine until I added a contact form plugin and now my editing for pages and posts only shows the html code, not wysiwyg.

Didn’t there used to be an HTML option – a button on the right hand side of the editing screen – in the older versions of WP?

I can’t seem to get it back to a simple editor, which is what I want to hand over to my client.

Thanks in advance.