Find below official SAP SD help documents.
Sales (SD-SLS)
Sales and Distribution (SD)
Sales and Distribution (SD)
Sales and Distribution
Sales and Distribution (SD) Workflow Scenarios
Sales and Operations Planning (LO-LIS-PLN)
Sales Employee (PA-PA)
Sales Support: Computer-Aided Selling (CAS)
Reports and Analyses (SD)
Pricing and Conditions
Shipping