Learn how to manage labels on an attachments using AMJ - Attachments Manager for Jira.
Follow these steps:
1. Click on any label assigned to the attachment or on the default gray label
2. This will direct you to edit the labels
3. By default, you will get the last 2 labels created by you as options after opening the app
4. Search for labels by typing them out
5. Create a new label by type the name
6. You will be given the option to create a label with that name if one doesn't already exist
7. When done editing the labels, click on the done icon to save
Note: As you edit the labels, you can click on the "x" icon to cancel any changes you made, and you will go back to the old state of the labels.