Sample Powershell script to

CreateAzureDbUser.ps1

param (
    [Parameter(Mandatory)] $ServerLoginName, 
    [Parameter(Mandatory)] $ServerLoginPass, 
    [Parameter(Mandatory)] $NewUserLoginName, 
    [Parameter(Mandatory)] $NewUserLoginPass,
    [Parameter(Mandatory)] $ServerName, 
    [Parameter(Mandatory)] $TargetDbName
    )

$MasterDbConnectionString = "Server=tcp:$($ServerName).database.windows.net,1433;Initial Catalog=master;Persist Security Info=False;User ID=$($ServerLoginName);Password=$($ServerLoginPass);MultipleActiveResultSets=False;Encrypt=True;TrustServerCertificate=False;Connection Timeout=30;"
$TargetDbConnectionString = "Server=tcp:$($ServerName).database.windows.net,1433;Initial Catalog=$($TargetDbName);Persist Security Info=False;User ID=$($ServerLoginName);Password=$($ServerLoginPass);MultipleActiveResultSets=False;Encrypt=True;TrustServerCertificate=False;Connection Timeout=30;"

Write-Host "Creating login user$($NewUserLoginName)"
$CreateUserLoginQuery = "CREATE LOGIN $($NewUserLoginName) WITH password='$($NewUserLoginPass)'"
Invoke-Sqlcmd -Query $CreateUserLoginQuery -ConnectionString $MasterDbConnectionString

Write-Host "Creating user $($NewUserLoginName) in target db"
$CreateUserInTargetDbQuery = "CREATE USER $($NewUserLoginName) FROM LOGIN $($NewUserLoginName)"
Invoke-Sqlcmd -Query $CreateUserInTargetDbQuery -ConnectionString $TargetDbConnectionString

Write-Host "Adding user $($NewUserLoginName) as db_owner"
$AddUsertoRolesInTargetDbQuery="EXEC sp_addrolemember 'db_owner', '$($NewUserLoginName)';"
Invoke-Sqlcmd -Query $AddUsertoRolesInTargetDbQuery -ConnectionString $TargetDbConnectionString