You can allow any of your customers to follow up on the ongoing works by following these set of steps:
1- Ensure that your web portal has the "register as a customer" function set on. If the choice doesn't appear, contact our support team for them to enable the customer registration portal.
2- Once done, have your customer register. Their request will be dropped under Security> Requests.
3- The following step is likely to be done by the time you receive a customer's registration request: update the customer account.
4- After receiving the request, you'll need to edit it (on the three-dot menu next to the request), select the company account from the dropdown list, and answer "YES" to whether the customer has been verified.
And, all set; your customer's login account will be created with a "customer" role by default. Note that this role narrows down access to the customer's current WO list.