Not all the information you need to collect for Contacts is a default field in Keela - that's because all organizations are unique and have unique data too. This is why we have Tags and Custom Fields! They provide a way to store all the extra information for your contacts that is also commonly used to create lists, or what we call Segments.
Ultimately, it's up to your organization's preference on whether you use Tags or Custom Fields for your various data sets, but here is a quick overview of each to assist you in this process!
Looking for ideas on how to segment your contacts? Check out our blog post here.