Can I add invoices used for Inventory managment

Is there any invoice option for inventory mangement

Have a look at the demo, these modules:

Product Groups

I’d say that Inventory management is not something you can do out-of-the-box, that is not SuiteCRM’s specialty (it’s not ERP, it’s CRM), but if your requirements are simple (like keeping a quantity of each product) it should be easy to achieve. If not, you’re better off using a specialized program and integrating it with SuiteCRM.