The existing habit
Your portal competes with the buyer's established ordering method.
In the US that method may be email, phone, an ERP template, or a representative who already knows the account. Compare the portal against that baseline using completion rate, error rate, support demand, and buyer feedback.
The minimum useful experience
Start with repeat purchase and account truth.
A buyer should sign in to their catalog, contract price, availability, terms, and recent orders. Reordering should take less effort than writing a message.
Company accounts
Model organizations, locations, roles, and approval responsibility.
Price lists and terms
Show the agreed commercial context without manual recalculation.
Fast reordering
Support lists, order history, SKU entry, and saved purchasing patterns.
Sales assistance
Let representatives help within the same system rather than creating shadow orders.
Operating model
Self-service should give sales better conversations.
Move repetitive lookup and order entry online, then use people for exceptions, specification, relationship, and growth. Adoption depends on changing the workflow after launch.
Decision
Calculate the cost of the current manual order.
Measure time spent finding price, checking inventory, entering orders, correcting errors, and reconciling accounts. That baseline is more useful than a generic feature list.