There are a number of options available to you from the cogwheel of a particular Discussion:
Each of these is available to admins by default, with access to other users managed using roles and permissions:
Please note that each of the above options depends on a user and category's permissions, which you can check by editing a role.
For more info on this, see the Roles and Permissions article.
You can read in detail about these options:
Depending on which addons you have available and enabled, you may see different options. The following addons may make an appearance here: