When you say make apps online do you mean like a chrome extension or an app for Apple products? If you mean apps for Apple I can help you as I am a developer myself.
The first thing you are going to want to do is buy a developer account. This is $100 per year so you will want to make sure you're serious about making apps. For the $100 you get an unlocked version of Xcode that makes it so easy to develop apps. You also get pre releases of the new software before anyone else does. now, if you want to make some money from your developer account you can sell spots to "testers" for a few bucks. By adding peoples UDID numbers to your account they can put the new software on their phone before everyone else too. Around new product and iOS launches sites pop up every doing this so jump on board with that too. You can easily make $500 doing this.
anyways, if you decided to get a dev account you'll want to head over to Google/Youtube and start looking at videos and tutorials as to how to do basic things. This is how I learned and it is a life saver. I first started googling how to make an image a link, how to change views, how to put a webpage into an app (it's called UIWebview), and so on. Theres so much stuff you can search that I'd never be able to list them all.
Learn the very basic things and then Google the rest. People post their code online and let you use it in your apps for free. Combine a bunch of these videos into your app and you will have your very first iPhone app