The My Account tab is the location where you can add your license key, see details about what you are licensed for and specify contact information.
License keys are tied to the account. Once a license key is added to an account it is tied to that account and can no longer be used on any other account even if you remove it from the first account. Each account can only have one license key at a time. If you add a second license key it will replace the first license key.
The contact info section is a location where you can add information about your account. This data is optional and can only be seen by the account administrators and by NeuShield.