OnDemand customers can get the Help Center link under the user menu(shown below) updated by contacting the support team.
This article describes how to update the target of the link.
OnDemand customers can contact support with the new URL they want the Help Center link to point to.
Agents should collect the new URL of the Help Center from the customer and create a ticket on PLNP of type Task.
Once the link is updated, you can validate by clicking on the Help Center link and confirm that it points to the desired destination.