With the correct permissions, Invoices can be created in both the Web Portal and the App.

To create Invoices using the Web Portal, go to CRM > Invoices > + New Invoice



To create Invoices using the App, go to  Accounts > Invoices > + (to create a new invoice)




Invoices can be created through a job, in the CRM contact itself and on the Web Portal Dashboard through Quick Actions Add New icon.