How to update personal information for Self Assessment profile

Hello, I need to change my personal details on my SA profile account. Including my telephone number. How can I do this? Recently, I am not receiving a login code via text message, so cannot log onto my account after putting in my government ID and password. How can this be resolved?

Hi,
If you are unable to log in to your online account you will need to contact our online services team for advice.
Technical support with HMRC online services
Thank you.