Out of the box, you'll have a few standard attributes, like Assignees and Status, and you can add any others that you'd like for your workspace from Settings → Attributes.
Click on the "New attribute" button, and then you can give your custom attribute a name and a type.
Many types of attributes are supported, including: text, multi-select, single select, date, users, and tasks.
If you choose multi-select or single select, you'll be able to add options with the "New option" button.
You can also add additional custom options to Status, so if you want to add one your team uses like, "In review", "Duplicate", or "Needs triage", you can also add those from Settings → Attributes.