I frequently run into a very frustrating issue on the iPhone. For most apps: it’s available on the screen keyboard but not in all apps. For example, in the first screenshot below the colon is available in the Drafts app. However, in the Amazon app it is not available. What gives? This was frustrating because I used : in front of shortcuts for text replacement. It appears that I’m going to have to change it to something else that is universal.
The one from Amazon is UIKeyboardTypeEmailAddress, a keyboard Apple supplies specifically for email address fields. The Amazon app is being a good iOS citizen by specifically using it. It doesn’t have a colon because generally speaking a colon is not a valid character in an email address.
A long while back I switched from using a semicolon to start my text replacement snippets to using “x” because the latter was more easily accessible in iOS (I believe this was a Katie Floyd suggestion).
Apple provides built in keyboards to App Developers.
There’s the standard one which appears in generic text fields, e.g. search in Amazon, but there are also specific keyboards for fields such as “email Address” which only includes the characters allowed in email addresses, plus a modifier for the extension, e.g. .com .net… The other one i’m aware of is the Number Keypad which only shows the numpad e.g. phone number fields.