Hi @Célia Boulbès ,
Welcome to the community!
If you add a label it will show automatically!
Have a look at this documentation: https://help.trello.com/article/797-adding-labels-to-cards
Just clear your browser data and after that log in to your account and I hope it will solve your problem!
Hello Community! My name is Brittany Joiner and I am a Trello enthusiast and Atlassian Community Leader. I'll be sharing with you a series of videos with my top tips on how to best use Trello...
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