The Iteration page allows you to add new iterations, and rename or remove existing ones. For each iteration, you can define a name - displayed throughout the project - and a description.
1. Open the Configuration page by clicking on the three dotted button, located on the upper-right corner.
2. Head to Configuration on the left panel, and click on Iterations.
3. Input Name and Description, then click on Add button.
3. Optional: Archive or Delete your custom Iteration. If your Custom Iteration is affected to any Test Case, you won't be able to delete it.