First, check Users -> Your Profile in your blog’s Dashboard and make sure that “Disable the visual editor when writing” is not checked.
If it isn’t, try deactivating all plugins. If that resolves the issue, reactivate each one individually until you find the cause.
If that does not resolve the issue, try switching to the Twenty Fifteen theme to rule-out a theme-specific issue (theme functions can interfere like plugins).
Hi James,
I did all that you advised and still, the only option have is html.
Hm, that’s odd.
Try downloading WordPress again and delete then replace your copies of everything except the wp-config.php file and the /wp-content/ directory with fresh copies from the download. This will effectively replace all of your core files without damaging your content and settings. Some uploaders tend to be unreliable when overwriting files, so don’t forget to delete the original files before replacing them.
