There are new fields on contacts for Customer Rank and Supplier Rank but they are not displayed by default.

If you create a contact from the Customer menu option it will have Customer Rank set to 1, and can then be selected as a customer on a Quotation / Sales Order.  Similar logic applies for suppliers / vendors.   

If you want to have a contact who is both a customer and a supplier, you could use the export / import tools, or you could create a Server Action to set both Customer Rank and Supplier Rank to 1 and then "Create Contextual Action" so that it can be selected from the "Action" dropdown for contacts.      

You need to be in debug mode to create server actions.  

Use Server Actions to set a contact to be a customer or supplier

Hi Divyesh:

Go to Settings > General Settings > Multi-Company and enable Inter-Company Transactions. After saving, you will get an option to Synchronize sales/purchase orders.