To try and rank your category pages higher in search engines you'll want to manually set the SEO settings. You can control the SEO settings for your categories by editing the Title, Description, and URL on your categories. Sometimes you'll want these to be different for search engines, than what your customers see.
Navigate to the category you want to add SEO for under Content > Categories and click Edit. Under the SEO tab set the SEO Title, URL Handle, SEO Description, and any Tags you want.
NOTE: As with all SEO changes, it may take a few days for changes to appear in search engines and when the link is shared.