To securely update your phone number on your Robinhood account, start by logging in to your account through the Robinhood app or website. After logging in, go to your account settings. Under the "Personal Information" section, you'll find an option to update your phone number. Enter your new phone number and submit the change.

Robinhood will send a verification code to your new phone number for security. Make sure to enter the code promptly to confirm the update.

If you encounter any issues or need assistance, you can always contact Robinhood support at +1(844) 478-5608. Their customer service team is ready to help with any questions or concerns.