On the iPad, you can tap the [+] button at the top while you're editing to get a popover with these things (images, sound effects, colors...). On the iPhone, there is an "Insert..." item in the copy/paste menu (when you don't have text selected) that does the same thing.
This is the community forum for my apps Pythonista and Editorial.
For individual support questions, you can also send an email. If you have a very short question or just want to say hello — I'm @olemoritz on Twitter.