Typically you want the approval of specific persons when deploying to Accept and/or Production. These kind of approvals can’t be configured in your YAML pipeline directly, but must be added via DevOps menu Pipelines/Environments. Note that this is not a setting for a specific pipeline, but for all pipelines that use the specific environment (and that’s actually what you want).
After you select the environment, you can click on the dots at the top and select Approvals and Checks. Specify the email addresses of the persons that should approve. Don’t forget to add your own account if you want to self-approve your deployments. For self-approve, set Minimum number of approvals required to 1 and check option Allow Approvers to approve their own runs.