Info pages are similar to man pages. They are not found with all commands but rather are generally associated with tools produced by the GNU Foundation.
You access info pages by typing info command_name. If there are no specific info page the man page will be shown.
Info pages have a node based structure and there are a number of commands you need to know to navigate through this structure. To get a detailed instruction on how to use info pages type info info into the shell.

Navigating in info

n - move to the next node
space - moves down a page frame within a node. You can read through the whole manual page by page if you want to.
Back Space or Del - moves up a page frame
b takes you to the beginning of the node
? shows you a summary of the commands. Use Ctrl+x 0 to quit the Help (The info help abreviates Ctrl as C). You can use ? when you are reading any info manual using an info reader so refer to that to learn the various options that are available to let you quickly navigate your way around an info manual or other texinfo based documentation that you are reading using info.