When it come to the business lead you can only convert that to a customer. Business lead allows you to enter and store information about potential customers. The information about the company, addresses and contacts can be stored. Also you can enter activities and define representatives for the lead.
You can create a customer from a business lead by using the right mouse button menu.

 Once you create the customer, you can use that customer to create a business opportunity.

Hi @beverly.mcconnell ,

When the business lead is converted to a customer/prospect, that business lead record is automatically deleted by the system, and no longer exists, since it has been converted to a customer/prospect. see below screenshot taken from the IFS help documentation.

Thanks,

Hi @beverly.mcconnell ,

Adding to the same, once the customer is created, you can create a business opportunity from the ‘Customer’ window itself via the ‘Contact’ tab using the contact line RMB option ‘Create Business Opportunity.’   

Once the Business Opportunity is created, it will open the created business opportunity if you say yes to the Question it asks whether you want to view it. Else, you can query for the customer ID in Business Opportunities window and find all the related business opportunities for that customer. 

Thanks,

Anushi Seneviratne