Here is the list of important SAP singles roles for Sales and distribution model (SD).
Inquiry Processing
Technical name : SAP_LO_SD_INQUIRY_PROCESSING
Contains functions for processing inquiries
Quotation Processing
Technical name : SAP_LO_SD_QUOTATION_PROCESSING
Contains functions for processing quotations.
Contract Processing
Technical name : SAP_LO_SD_CONTRACT_PROCESSING
Contains the functions for processing contracts.
Sales Order Processing
Technical name : SAP_LO_SD_SALES_ORD_PROCESSING
Contains the functions for processing sales orders.
Scheduling Agreement Processing
Technical name : SAP_LO_SD_SCHED_AGR_PROCESSING
Contains the functions for processing Scheduling Agreements.
Returns Processing
Technical name : SAP_LO_SD_RETURN_PROCESSING
Contains the functions for processing returns and delivering goods.
Rebate Processing
Technical name : SAP_LO_SD_REBATE_PROCESSING
Contains the functions for processing rebate agreements and displaying and updating billing documents.
Sales Deal and Promotion Processing
Technical name : SAP_LO_SD_DEALS_PROMOTI_PROCES
Contains the functions for processing sales deals and promotions.
Display Customer and Material Information
Technical name : SAP_LO_SD_INFORMATION_DISPLAY
Contains the functions for displaying information on materials, for displaying customer-specific information and customer material info records.
Online Billing Processing
Technical name : SAP_LO_SD_BILLING_PROCESSING
Contains the functions for online billing processing and retroactive billing.
Billing Processing (In The Background)
Technical name : SAP_LO_SD_BILLING_BATCH_PROCESSING
Contains the functions for executing billing processing in the background.
Invoice List Processing
Technical name : SAP_LO_SD_INVOICELIST_PROCESSI
Contains the functions for working with invoice lists.
Maintain Customer and Material Information
Technical name : SAP_LO_SD_INFORMATION_PROCESSING
Contains the functions for maintain customer-specific information and material information on the customer.
Display Pricing
Technical name : SAP_LO_SD_PRICING_DISPLAY
Contains the functions for displaying pricing data for a material.
Maintain Pricing
Technical name : SAP_LO_SD_PRICING_MAINTAIN
Contains the functions for defining pricing.
Release Blocked Documents for Billing
Technical name : SAP_LO_SD_BLOCKED_BILLING_DOC
Contains the functions for releasing blocked sales documents.
Release Sales Orders for Delivery
Technical name : SAP_LO_SD_RELEASE_FOR_DELIVERY
Contains the functions for releasing blocked sales orders.
Display Sales Information
Technical name : SAP_LO_SD_SALES_DISPLAY
Contains the functions for displaying sales information.
Display Billing Documents
Technical name : SAP_LO_SD_BILLING_DISPLAY
Contains the functions for displaying billing documents.
Sales Analysis
Technical name : SAP_LO_SD_SALES_PERFORMANCE
Contains the functions for analysis and Controlling in Sales.
Credit Management in Sales and Distribution Documents
Technical name : SAP_LO_SD_CREDIT_MANAGEMENT
Contains the functions for credit manager.
Backorder Processing
Technical name : SAP_LO_SD_BACKORDERS
Contains the functions for processing backlogged sales orders, and their rescheduling.
Sales Support
Technical name : SAP_LO_SD_SALES_SUPPORT
Contains the functions for processing pre-sales activities.
Output Processing
Technical name : SAP_LO_SD_OUTPUT_PROCESS
Contains the functions for sending information in sales area.
These are the important single roles in SAP SD.
Also Read : SAP SD Module Tutorial -> SD Transaction Codes -> SD Tables