SOAP API Passing credentails to XML envelop

I’m working on an integration with Clarity( Broadcom) - using a soap execute to import data from a Query.
In the soap envelope – I need to pass Username and Passoword for authentication . How can I pass credentials securely from account ( basic OAUTH)? It is not taking parameters like account.Username and account.passoword ?

<soapenv:Envelope xmlns:obj="" xmlns:soapenv="">
           <Query xmlns="">