@Murillo Heldt Gomes Martins ,
You could contact you IT Admin to add your mobile phone number in Azure Active Directory admin center > Users > choose your account – profile > update your office number in Contact info. For more details, please refer to this article.
Besides, Teams doesn’t support to register phone number. Each account should be created by IT admin. If I misunderstand you, please give us more information to know your scenario.
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