Notes. the app that comes pre-installed with your iPhone, is a very simple but handy little tool.
Of course it creates notes, as the name implies. Anytime I have a nice business idea, I can jot it down in Notes and reorganize it later (e.g. in my business plan). I simply need to email it to myself.
Also, at this very moment, for example, I am using iphone Notes to write this blog article because I have no WiFi coverage and don't want to connect over the mobile provider- I want to save up some of my free monthly data that came with my iPhone plan. Later on I will email this note to myself and copy and paste it into the blog.
Another very useful business use for iPhone notes is creating some standard email responders or email signatures. On our Mac's Mail program I have the ability to create ready signatures. I exploit this ability not only to create standard email signatures with my name and contact details but to have ready responses to standard client enquiries such as when I send out a detailed pricelist. However, Mac Mail Signatures are not available on the iphone Email program. Nevertheless, one can create the same standard responses in iPhone Notes and then press the email button (the envelope icon). This will automatically copy-paste your note into a new email in the iPhone email program. Very handy productivity and efficiency tool for business users with a Mobile Office, i.e. their iPhone in their pocket.
Apart from business uses, I use Notes for writing down books, music and cinema films I am interested in. For example, I have one note that I call "films" where I note films of interest when I hear or read about them. This way, I immediately know what I'm looking for next time I walk into Blockbuster's. When I have seen a film I delete it from the note.
Even the standard iPhone apps that came pre-installed can be used smartly to increase your efficiency and productivity while you're on the go with your "Mobile Office".