How can I inject Azure DevOps pipeline run number in a build artifact file?

I would like to have the Azure Devops pipeline build identifier (in red below) displayed in my deployed Angular app. Any suggestion on how can I do it, please?

You need to use $(Build.BuildNumber) variable to get this value. And now it depends what you have already in your angular application.

For instance you can set this value in environment.ts file

// environment.ts environment variables
export const environment = {
  production: false,
  APIEndpoint: 'https://dev.endpoint.com'
  buildNumber: '#{Build.BuildNumber}#`
};

Via Token replace extension

- task: qetza.replacetokens.replacetokens-task.replacetokens@3
  displayName: 'Replace tokens'
  inputs:
    targetFiles: |
      **/environment.ts

You need to run this step before you compile angular app so the value reach your config.