Google SERPs started showing Emoji's in the Title tags and Meta Descriptions of the pages from May 2015. Click here for more information.
Here are the steps to add Emojis to your WordPress Posts or Pages.
Step 1: Go to iEmoji.com and find the emoji you want.
iEmoji.com has a huge collection of emojis. The emojis are categorized and you can also search them using the search bar.
Once you have found an emoji you want to use look for the “Decimal HTML Entity” or “Hexadecimal HTML Entity”. Copy either codes and paste it in your “SEO Title” or “Meta Description” section of the SEO plugin.
Here is what the preview with an emoji looks in WordPress SEO by Yoast plugin: