Hello,
Unfortunately, There is no such option in theme settings available to change the size of share buttons on the single blog page.
You need to add the following Custom CSS in the Global Custom CSS area under Theme Settings >> Custom CSS.
.single-post-social .woodmart-social-icons {
font-size: 15px;
}
You can adjust the font-size according to your requirements.
The URL you shared is WoodMart element but if you want to style it then you will need to use the social button module of the WoodMart in every single blog post.
Best Regards.