With the help of Facebook's Share Button Configurator, you can easily create and embed share buttons into your website.
1. Open Share Button Configurator and create the button:
Enter the URL of the page that you'd like to share on Facebook
Select the button layout
Choose the button size
When you're done, click Get Code:
2. Open the IFrame tab and copy the code:
3. Paste the code anywhere on your website using the embed code element:
4. Finally, update your website for the changes to reflect online.