To add an MX record on the "Email Settings" page, please follow these steps:

1. Sign in to your Dynadot account.
2. Click "My Domains", and "Manage Domains" from the left-side menu bar.
3. Check the box next to your domain name(s) and click on the "Action" button.
4. Choose "Email Settings" from the "Action" list.
5. On the "Email Settings" page, select the "MX records" setting from the top drop-down menu.
6. Enter the MX value in the "Mail Host" field and the priority in the "Priority" field. Priority 0 is the highest priority.
7. Click on the "Save Email Settings" button to save your changes.