You can use input text with "list" attribute, which refers to the datalist of values.
<input type="text" name="city" list="cityname">_x000D_
<datalist id="cityname">_x000D_
<option value="Boston">_x000D_
<option value="Cambridge">_x000D_
</datalist>
_x000D_
This creates a free text input field that also has a drop-down to select predefined choices. Attribution for example and more information: https://www.w3.org/wiki/HTML/Elements/datalist