Hello @DaphneS7. At this time, the editor you are currently using to create your campaigns does not have the ability to exclude by tag. You would have to create a list of these contacts by using Advanced Search. You can narrow them down by selecting the list and excluding a certain tag or all tags.
However, our next-generation editor does have this feature where you can send to contacts who do not have a tag. If you would like, we can turn on this editor for you so you can take advantage of this feature.
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