1. View the page. If the page already has labels, these will be listed at the bottom of the page below the page content.
2. Click the 'Add Labels' or the 'Edit' link beside the list of labels.
3. An input field will open below the existing labels. If available, it will also show you a list of 'suggested labels'. These are the labels that you have used recently and the most popular labels in the space. Your personal labels will also appear here if you have used them frequently or recently. Check if you want to use any of the suggested labels. Click a label to add it to the page.
4. If you want to add a new label, simply type it in and click 'Add'. As you type, the drop-down field will display the label closest to the word you are typing. It is possible another user may have added the same label or a similar label which you can select and reuse.
5. Click 'Done'.

Labels are always in lowercase. Even if you use uppercase characters, Confluence will convert these to lowercase when it adds the label.