There is no colon on my iPhone keyboard

Email addresses cannot have colons. Its not possible, its not allowed, in the email address definition. There's no such thing as an "https email address".

https refers to a secure website address not an email address. You cannot enter an website address in an email field.

The colon is not available if you're in an email address field - presumable because you cannot have a colon in an email address.

Which keyboard do you have?

DM28 wrote:

Even when I press the 123 key on my iPhone keyboard, there is no colon. Where is it? I can’t enter an https email address in contacts without it!

There is no such thing as an "https email address".