List options without typing on autocomplete Is it possible to show options when user clicks to the input field instead of showing after typing at least one matching character? 

Autocomplete starts showing the options after user types one character but it is hard to guess for new users what's the possible options for related field.
A possible solution is to show the field as a select list and then use the chosen module to get the functionality of searching through the options.

From the module's description:


  You can force enable/disable Chosen for certain field widgets: Select list (for both list and date fields), and Select (or other) list. If you have a field using one of these widgets, in the field settings, you will find a Apply Chosen to the select fields in this widget? option with three values: Apply, Do not apply, or No preference (which will fall back to using the automatic application).