Tags (sometimes known as labels) can be added to cards to help categorise them and keep things organised. You can then filter cards by ‘Tag’ in boards and Saved filters.
When adding a tag to a card you can select from the list of existing tag, or create a new one. When you create a new tag, that tag is created on a per Space basis.
For example, if I create a tag ‘Blog Post’ on a card in the ‘Marketing’ space, that tag will only be available within the ‘Marketing’ space. This prevents irrelevant tags spilling over to other teams boards and workflows.
If you move a card to a different space, only the tags that are in use by both spaces will be preserved on the card.
Edit a Space tag’s name or colour
To edit a space tag, open the tag picker dropdown on a card, hover over the tag, and then click on the ‘pencil’ icon to go into edit mode. This will allow you to change the tag’s name or colour. This will rename the tag and colour on all the cards the tag has been added to.
Delete a Space tag
To delete a space tag, open the tag picker dropdown on a card and hover over the tag. Click the ‘pencil’ icon to go into edit mode, and then click the trash can ‘delete’ icon. This will permenantly delete the tag and remove it from all the cards it was added to. This action cannot be undone.
Workspace tags are universal tags that are avaliable in every Space within your Workspace. For example, if you want to create a common tag like ‘bug’ that can be used in any Space, create it as a Workspace tag.
Workspace tags can be created and edited here Settings > Workspace > Tags
Smart tag merging
Workspace tags help you keep tags organised and consistent. When creating a workspace tag, we’ll check to see if a Space level tag with the same name already exists. If it does, we’ll merge the Space level tag into your new Workspace tag.
When Superthread decides to merge tags, only the tag’s name is considered. The colour and capitalisation in the tag name is ignored. For example, an orange Space level tag called ‘bug’ (written in lower case) will be mereged into a red Workspace tag called ‘Bug’ (capitalised) because their names still match. 
