Keyboard changes from numbers to letters while typing password

Everytime I want to type in a password, which now requires numbers, letters, special characters, capital letters, the keyboard automatically switches to alphabets after typing 1 digit. And if there are multiple numbers, 90% of the time, the password is incorrect (obviously). How do I get rid of this annoying glitch. And is there an option to completely delete Apple Keyboard software from the phone? (I've never used it apart from Passwords, which is forced anyway)