This chapter describes various advanced Info commands. (If you are using a stand-alone Info reader, there are additional commands specific to it, which are documented in several chapters of GNU Info in GNU Info.)
One advanced command useful with most of the others described here is C-q, which “quotes” the next character so that it is entered literally (see Inserting Text in The GNU Emacs Manual). For example, pressing ? ordinarily brings up a list of completion possibilities. If you want to (for example) search for an actual ‘?’ character, the simplest way is to insert it using C-q ?. This works the same in Emacs and stand-alone Info.