Special input field HTML (this is really for the specialists)

I want when I am on an input (text)field to have the possibility to chose from a list or type something myself.
Please check https://jqueryui.com/autocomplete/ . When you enter a character that is in the list, you get a list of possibilities containing that character. I want however always the complete list when I get in that field (focus).
And I want also the possibility to type something else (which is not in the list). So choice: from the list or own text.

Secondly I want to have the possibility to decide to click after that field on a symbol to put my input text which is not in the list, to be part of the list in the future. My own texts will appear in another colour in the list in the futur.