> For the complete documentation index, see [llms.txt](https://docs.church.directory/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.church.directory/core-concepts.md).

# Core Concepts

- [Users](https://docs.church.directory/core-concepts/users.md)
- [Login Methods](https://docs.church.directory/core-concepts/users/login-methods.md): Church Directory offers 3 different methods of logging in for members:  email, username and phone number.
- [Account Membership](https://docs.church.directory/core-concepts/users/account-membership.md): Account membership terminology can be confusing based on other systems use of this language. We'll try to clear that up here.
- [Family Units](https://docs.church.directory/core-concepts/users/family-units.md): Family units in Church Directory are a key part of how information is displayed throughout the app, especially in regards to the Directory.
- [Family Emails](https://docs.church.directory/core-concepts/users/family-emails.md)
- [Church Offices](https://docs.church.directory/core-concepts/users/church-offices.md): A "church office" (sometimes called a "church role" in congregations) are titles such as "Elder", "Deacon", "Minister", "Evangelist", etc.
- [Groups](https://docs.church.directory/core-concepts/groups.md): Groups are a special and import part of Church Directory for organization and communication.
- [Group Posts](https://docs.church.directory/core-concepts/groups/group-posts.md): Group Posts is a super-low cost communication platform built right into Church Directory.
- [Texting (SMS)](https://docs.church.directory/core-concepts/groups/texting-sms.md): Church Directory allows your congregation to text groups. The texting tool, utilizing a dedicated toll-free number, is meant for one-way communication to mobile numbers stored in the
- [SMS and Text Encoding](https://docs.church.directory/core-concepts/groups/texting-sms/sms-and-text-encoding.md): SMS messages use a special and limited character set.
- [Texting (MMS)](https://docs.church.directory/core-concepts/groups/texting-mms.md): Church Directory also allows your congregation to text groups for quick communication via MMS.
- [E-mailing](https://docs.church.directory/core-concepts/groups/e-mailing.md): Church Directory allows your congregation to email groups for easy communication.
- [Email Costs](https://docs.church.directory/core-concepts/groups/e-mailing/email-costs.md): Why do you charge for emails?  Shouldn't emailing be free?
- [Voice Calls](https://docs.church.directory/core-concepts/groups/voice-calls.md)
- [Numbers for SMS & Voice Calls](https://docs.church.directory/core-concepts/groups/numbers-for-sms-and-voice-calls.md)
- [Messaging Policies](https://docs.church.directory/core-concepts/groups/messaging-policies.md)
- [Communication Use Policy](https://docs.church.directory/core-concepts/groups/messaging-policies/communication-use-policy.md): Church Directory has strict use policies for sending emails, SMS and voice calls.
- [SMS message length limits](https://docs.church.directory/core-concepts/groups/messaging-policies/sms-message-length-limits.md): Church Directory follows the technical 160 character limit per SMS.
- [Roles](https://docs.church.directory/core-concepts/roles.md): Roles are different from Groups in that they are only used determine what access a user account has to Church Directory.