inbound link= incoming link from others site
internal link= linking to one page to another page in our site.
indexed pages= our page link appear in google search result.
An internal link is a type of hyperlink on a webpage to another page or resource, such as an image or document, on the same website or domain. Hyperlinks are considered either "external" or "internal" depending on their target or destination.
Source: https://en.wikipedia.org/wiki/Internal_link
Indexed pages have been found by search crawlers and deemed to have enough quality for relevant search phrases. Indexed pages will show up in search results and can drive organic traffic to your site.