How to add Services selector to Accounts module?

When we open an Account, we would like to be able to scroll to the bottom section of the Account, under the Services Purchased section (see image

) and be able to either Add or Select a Product/Service in order for us to easily see what services we can push next onto a client.

How do we make that button appear in that section please? Must have the Add or down arrow, select option.

Many thanks!

That subpanel is closed related to the Invoices module (Not sure if related to contracts and quotes as well). Products displayed there had been added to a quote/invoice previously.