Hi Stacie,
Generally vendor is classified by use of material, If you want to use service material the will search service vendor, if you want to procurement of material at random in a year or under urgency you can create one time vendor, to procure material regularly treat as regular vendor. For consignment (external procurement ) use consignment vendor and so on. If you want to optimize you procurement then you can maintain vendor evaluation. So keep searching on Google and sap.help a lot of note will get in detail. Kindly elaborate your question so that expert can help you.
Regards
Sanjeet Kumar