For those who enter certain words or passwords often, you can create shortcuts that let you enter them much more quickly. For example, you can type “omw” and your iPhone will automatically enter it as “On my way.”
In Settings, navigate to General>Keyboard>Shortcuts>Add New Shortcut. Then, enter the word or phrase, as well as its shortcut. This is especially handy for passwords; enter the shortcut into the username field, then paste the password into the password field. Bonus: You can create shortcuts for emoji, too.