, or 致（いた）す
as it is often written, is a 謙譲語（けんじょうご） (humble speech) う-Verb
, which refers to the actions of the speaker (or people within the speakers inner circle, like their company). Similarly to お〜する
means ‘to do’.
In the case of する
verbs themselves, simply replace する
. For other verbs, add いたす
to the ます stem of the verb, while attaching お, or ご to the beginning (depending on whether it is a word of Japanese or Chinese origin).
Words that include the kanji 拝（はい） ‘to worship’, or ‘to revere’, do not usually require お, ご, or いたす
. This is due to the word itself being ‘respectful’.
I will look at my relatives' temple. (With utmost respect)
I will borrow money from my senpai. (With utmost respect)
いたす is considered to be slightly more humble than お〜する, which means that it will be heard more frequently in advertisements, or being used by company employees.