How Do I Link This To My Existing Marriott Bonvoy Account?

If you have an existing Marriott Bonvoy membership number, you will be prompted to enter this when activating your card via  Marriott Bonvoy Debit Card App. 

If you don’t provide your existing membership number during activation, a new Marriott Bonvoy membership number will be generated for you. In cases where an existing member receives a second membership number, the two accounts must be merged into one. To merge Marriott Bonvoy accounts, please visit: https://help.marriott.com/s/article/Article-22511