Can others add options to my poll?

Allow others to add options in a new poll

To allow others to add new options to a new poll you are creating, check the box for Allow options from others under the Settings section during the creation of the poll. 

If you are creating a poll using the /poll command, you can add the keyword allow-options to enable this setting:

Both approaches would result in a poll that shows the Add option button. Others can click this button to add a new option to the poll:

Clicking the Add option button will allow others to enter an option that will be added to the poll and can be voted on by all:

Allow others to add options to an existing poll

You can also allow others to add options to an existing poll you have created. To do that, click the 3-dot button to open the menu and select Edit Poll:

Under the section for Poll Settings, simply check the box for Allow options from others:

This will add the Add option button to your existing poll and allow others to add new options to the poll: