class CreatePollForm(FlaskForm):
    title = StringField('Title', validators=[DataRequired()])
    options = FieldList(StringField())
    submit = SubmitField('Create')

<ul id="options">
        <li>
            <label for="options-0">Options-0</label>
            <input id="options-0" name="options-0" type="text" value="">
        </li>
        <li>
            <label for="options-1">
                Options-1
            </label>
            <input id="options-1" name="options-1" type="text" value="">
        </li>
        <li>
            <label for="options-2">Options-2</label>
            <input id="options-2" name="options-2" type="text" value="">
        </li>
   ...........
    </ul>