Go to https://trello.com and log in to your account.

Click on the card you want to add a label to.

Click the "Labels" button in the right sidebar.

Select the label you want to add from the list of available labels.

Click the "Add" button to add the label to the card.

trello.com

If you are using Trello to manage projects, tasks, or other items, you may want to add labels to cards in order to better organize and categorize them. Labels can help you quickly identify cards that are related to each other, or that need to be addressed in a certain way. Knowing how to add labels to cards in Trello can help you better manage your projects and tasks.

Want to make guides like this in seconds? Yes, it's really that fast.