Arduino Reference is an Arduino Language Reference.
In this app contains ads and potentially in-app purchases you can access content online for free at https://www.arduino.cc/en/Reference/HomePage divided in three main parts: structure values (variables and constants) and functions.

Features:
★ No Ads (In-App Purchase)
★ Search tools (In-App Purchase)
★ Full part of content (In-App Purchase)
★ All content offline available
★ Change the Themes (Light Dark Black)
★ Change the code style theme (Light Dark)
★ Change the font size
★ Syntax Highlight for Arduino language
★ Serial Monitor for debugging needed

Tutorial upload sketch over bluetooth:
https://www.hackster.io/mansurkamsur/how-to-make-bluetooth-shields-for-upload-sketch-to-arduino-96b182