Suppliers and manufacturers
A 'Supplier' is an external company that distributes parts and materials to other companies. These parts and materials are not likely produced by the supplier, unless they are also a manufacturer. A 'Manufacturer' is a company that produces, or manufactures, parts and materials. When looking to assemble your final product, you must decide where each physical component is going to come from, and this helps drive the item type and item attributes you configure for each component in your assemblies.
Suppliers can be associated with any item type and this enables you to send that supplier a Request for Quote, or involve them in a QA process or Requirement. You can do this for multiple suppliers. This can help you determine who can provide you with what you need at a reasonable cost.
Manufacturers are associated with Purchased items (mechanical, electrical, and electromechanical) only. This is because these items can be purchased "as-is". When you create a new purchased item, you should fill out the Manufacturer and the Manufacturer’s Part Number (this is the manufacturer’s own catalogue number for the part) so that others know where this item is going to come from.