The standard D365 CE sales pipeline runs through four tables, each representing a stage of maturity in a deal.
Lead
An unqualified potential sale — a name and some interest, not yet confirmed as viable. Leads are typically qualified (converted) into an Account, Contact, and Opportunity, or disqualified and closed out if they’re not a fit.
Opportunity
A qualified, in-progress deal, tracked through sales stages (often via a Business Process Flow — Qualify, Develop, Propose, Close) with an estimated value and close date. This is where most day-to-day sales activity and forecasting happens.
Quote
A formal, line-itemed price proposal generated from an Opportunity’s products, which can be revised, sent to the customer, and ultimately won or lost. Only one quote per Opportunity can be active at a time, though multiple draft revisions can exist.
Order
Created once a Quote is won — represents a confirmed, committed sale ready for fulfillment or invoicing. From here, data often flows out to a separate finance/ERP system (which may or may not be Dynamics 365 Finance & Operations) for actual invoicing and fulfillment.
Why this matters beyond “knowing the tables”
Understanding this chain is what lets you reason about automation and reporting requests sensibly — “notify the account manager when a Quote is won” is really “trigger off the Order being created,” and forecasting reports are built on Opportunity estimated revenue and close dates, not Orders. Mapping a request to the right table in this chain is half the work of answering it correctly.