If you do not require invoicing on AccountancyManager, you can switch this off. To action this, go to Settings > Account Settings. 

Scroll to the Hide Unrequired Features section on the left and tick the box for Hide Invoicing. 

Once this is done, scroll to the bottom of the page and click Save Settings on the right.

You will no longer be able to see Invoicing in the toolbar along the top of AM.

Invoices will no longer be available in the client file either.

If at any time you would like to turn Invoicing back on, you can follow the steps above to enable it again.