The phone number is what customers use to reach your business through WhatsApp. This guide covers the requirements, verification, and the mistakes to avoid when setting it up with Mersal.
5 min read·Updated
Phone number requirements
Your number must be able to receive a one-time code by SMS or voice call, and it should be a number your business controls for the long term.
Able to receive OTP by SMS or voice callOwned and controlled by the businessNot currently active on the regular WhatsApp app when migratedRecognisable to your customers
Can I use my existing WhatsApp number?
Often yes. An existing number can be moved to the WhatsApp Business API if it meets the requirements and is not active on the consumer WhatsApp app at the time of migration. Moving a number is a one-way step, so plan it carefully.
OTP verification
During setup, Meta sends a one-time code to the number by SMS or voice call. You enter that code to confirm you control the number. If the code does not arrive, check that the number can receive external SMS or calls and try the voice option.
Number ownership
The number should belong to the business, not to an individual employee. Using a personal number risks losing access if that person leaves, and can complicate quality and template ownership.
Common setup mistakes
Using a number still active on the regular WhatsApp appUsing an employee’s personal numberA number that cannot receive OTP externallyChoosing a number customers will not recognise
Reconnecting or changing a number
You can change or reconnect a number later, but it may affect your customers, templates, quality rating and setup. Treat a number change as a planned migration, not a quick edit.
Changing numbers later may affect customers, templates, quality and setup. Contact Mersal support before migrating a live number.
Key takeaways
Use a business-owned number that can receive OTP.It must not be active on the regular WhatsApp app when migrated.Changing a number later affects customers, templates and quality — plan it.
Frequently asked questions
Usually yes, if it meets the requirements and is not active on the regular WhatsApp app when it is migrated.
Confirm the number can receive external SMS or calls, then try the voice call option. If it still fails, contact Mersal support.
No. Use a number the business owns and controls, so access and quality stay with the business.
Was this helpful?
Still need help?The Mersal team can review your setup and guide you through the next step.