Calls work as soon as you buy a number. Texts do not, and the reason is not us.
US carriers — AT&T, Verizon, T-Mobile — require any business sending texts from a ten digit local number to be registered: who you are, your tax ID, and what you intend to send. Unregistered texts are not rejected, they are filtered: you would see "sent" and your customer would get nothing.
What you fill in
Settings → Texting registration.
What happens next
It goes to the carriers in three stages, shown separately because they are approved by different people and fail for unrelated reasons. The brand usually clears in hours; the campaign takes days.
You will be told when it is approved. Nothing else needs doing — the number is attached automatically and texts start going out.
While you wait
Calls and the assistant's replies work normally. Only texts your business starts — an invoice sent by text, an automatic reminder — wait for approval. Reminders set to go by text are sent by email in the meantime rather than skipped.
If you are a sole proprietor without an EIN
Tick the box. It is a different, lower volume route, and the only one that texts a confirmation code to your mobile.