Internal link
An internal link connects one page of your site to another page on the same domain.
Internal links are the navigation backbone of a site. They help users move between related pages and, just as importantly, let search engines discover your content and understand how pages relate to each other. Unlike an outbound link, an internal link keeps both the user and the link equity on your own domain.
Strategically, internal links let you channel authority from your strongest pages to the ones that need a boost. Linking from a high-authority pillar page to a thinner page (with descriptive anchor text) is one of the most reliable, fully white-hat ways to improve rankings. They also rescue orphan page URLs, which receive no internal links and are therefore hard for crawlers to find.
A common quick win is to find striking distance keywords (pages ranking on page two) and add a few internal links to them from relevant, authoritative pages on your site. Because you control every internal link, this is the lowest-risk lever in SEO, with no outreach or budget required.