When you want to import contacts with multiple tags in one field into your MailBlue account, you need to make sure before importing that these tags are all in one column in the CSV file and separated by a comma.
The cell behind your contact will then look like this, for example: ice, cookies, cake
It doesn't matter if you use a space between the tags or not. All tags will be added separately to the contact in your MailBlue account.
Next, it is important to assign the 'tag' field to the 'tags' field on the import page.