To make the keyboard shortcuts (as mentioned by caq), go to the General tab in your Settings app and press the line titled "Keyboard." Scroll to the bottom to the line titled "Shortcuts."
At the top right, there's a plus sign; tap it to enter a new shortcut. Just know that "phrase" is what you'll get when you type the "shortcut."
I use several shortcuts - two of the most used ones are for my e-mail addresses. For example, I use "gm" to be the shortcut for my Gmail address.
Then, with the shortcut created, you'll be able to enter your e-mail virtually anywhere.
Marilyn