You will need the Limited SMS permission to send texts, the Full SMS permission for keywords, and the Limited Account permission to activate or release a number. With more than one organization, what limits you is which organizations you can reach.
Once your account has two or more organizations, each organization holds its own texting number and its own list of people who agreed to receive texts. This article explains how that works in one place: numbers, consent, sending, keywords and costs.
One number per organization
Each organization holds at most one texting number. The number is what tells a member which organization is texting them.
Verification status belongs to each number. Only a Verified number can send.
Activating a number costs $5 and needs the Limited Account permission. With more than one organization, you also need access to every campus, and you choose an active organization within your reach.
Releasing a number needs Limited Account and an active organization within your reach. It does not need access to every campus.
How do I enable text messaging? covers activating a number.
Consent is per organization
Agreeing to texts from one organization, or stopping them, does not change any other organization.
The public opt-in page belongs to one organization.
A form's opt-in box consents to the form's one active organization, otherwise the default organization.
A carrier-level block is recorded only for the organization that sent the text.
What is text messaging consent? explains the kinds of consent.
Why STOPALL does not stop all
When someone texts STOP, END, QUIT, STOPALL, CANCEL or UNSUBSCRIBE to an organization's number, it stops texts from that organization only. Even STOPALL stops just the organization whose number was texted.
The person gets one confirmation text.
Staff cannot undo the stop. Only START or UNSTOP texted from that phone clears it.
JOIN then CONFIRM also clears it, but after a STOP the JOIN invitation is not delivered. Tell people to text START.
Email works the other way. Text consent is per organization, but an email unsubscribe covers every organization. The public email preferences page tells the person this when they unsubscribe.
Example: Riverside Community and Riverside Academy each have a number. A parent texts STOP to the Academy's number. They stop getting Academy texts, and Riverside Community can still text them. If that parent is emailed by the Academy and unsubscribes, they stop getting general email from both.
Sending texts
Send From - the screen requires you to pick the organization a text comes from. It must be an active organization within your reach, with a verified number.
One text per person - each recipient gets one text, from an organization they consented to that has a verified number. That is the default organization if it qualifies, otherwise the lowest one that does.
Never another organization's number - a text never borrows another organization's number. People who cannot be reached are skipped and counted as no number, opted out, or not opted in.
Automated texts - go from the organizations that own the record, or from the default organization when there is no record. They are skipped when no owner has a verified number.
Replies - go out from the number that was texted, and the reply email goes only to that organization's reply person.
Scheduled texts - store one organization, or every organization when sent from the app or API with no Send From. If that organization is archived or unverified by the time the text goes out, it records Not sent rather than using another number.
Keywords
A keyword answers on the numbers of the organizations it names, and of the organizations its campuses belong to. A keyword that names neither answers on every number.
Two organizations can each have a keyword with the same word, as long as no single number answers both.
How do I set up keyword text messaging? covers setting them up.
Costs
One prepaid balance pays for texts from every organization. Changing the balance or auto-recharge needs Full Account, and access to every campus when you have more than one organization.
Activating a number costs $5.
A $5 non-usage fee is charged per number for any month when no text was sent or received on it. Numbers still pending are skipped.
Text messaging is not an add-on seat. An organization has it by holding a number.
How much do text messages cost? has the full pricing.
Edge cases to know about
Warning: A STOP can go unrecorded in two situations. Texts to an unverified number are ignored, so a STOP sent to one is recorded nowhere. And once a number has been released or its organization archived, a STOP texted to it is only honored for about a day (see below). Keep this in mind before you release a number or archive an organization.
Archiving an organization releases its number.
A STOP to a number your account no longer holds stops every active organization, but only while that number still points to your account. Releasing it from the Messaging Center, or archiving its organization, breaks that link within about a day. After that, a STOP to it is dropped and recorded nowhere.
An opt-out recorded by staff is soft. Staff can clear it, and transactional texts still reach that number.