Creating a new or converting a retail customer into a wholesale customer gives you the ability to do the following:
Add multiple contacts to that user
Unlimited addresses and ability to set default billing and shipping
Set a default discount % to apply to their orders
Select a wholesale price list so when creating orders it will use those set prices
Set standard payment terms such as "Net 30 days"
Default currency & delivery method
Minimum order value, below which an order can not be created
To create a new B2B customer
Go to Setting
Click on Customers
Click + New Customer
Change customer type to be "Wholesale"
Fill in your wholesale customer's details

Note: When creating a Wholesale customer, ensure that ALL contact information, aswell as address and billing information is entered.
Account Number[Optional]: Set account number for that customer.
Customer Notes[Optional]: This will be visible to your team when creating an order for this customer.
Price List[Optional]: The default prices to use for this customer. Learn how to create new price lists.
Payment Terms[Optional]: How many days until your customer must pay you. When used orders for this customer will go into "Ready to Ship" without a payment.
Minimum order value[Optional]: You will not be able to create an order for this customer if the order total is less than this amount.
Default Discount %[Optional]: This % is applied as a discount to order total when creating an order for this customer.
Converting an existing customer to a Wholesale customer

Find the customer first by going to Settings
Click on Customer
Use the Search customers box
or click into the customer and click the edit icon in the top right-hand corner

Click the "Retail type" dropdown and select Wholesale.
The next screen lets you add wholesale detail but looks a little blank, don’t worry the customer information is still saved.