Sample Azure pipeline for building and distributing multiple generated APKs to Visual Center AppCenter for release. App center distribute template here: https://gist.github.com/James-Aidoo/0f7eb562ec69da6e1fe3a01152db7acd

azure-pipeline.yml

# Variable 'Key.StorePassword' was defined in the Variables tab
# Variable 'Key.Alias' was defined in the Variables tab
# Variable 'Key.Password' was defined in the Variables tab
# Variable 'Key.StoreFileName' was defined in the Variables tab

variables:
- name: BuildParameters.wrapperScript
  value: gradlew
- name: BuildParameters.tasks
  value: assembleRelease
trigger:
  branches:
    include:
      - develop
name: $(date:yyyyMMdd)$(rev:.r)
resources:
  repositories:
  - repository: self
    type: git
    ref: develop
jobs:
- job: Job_1
  displayName: Agent job 1
  pool:
    vmImage: ubuntu-20.04
  steps:
  - checkout: self
    clean: true
  - task: Gradle@2
    displayName: gradlew assembleRelease
    inputs:
      wrapperScript: $(BuildParameters.wrapperScript)
      tasks: $(BuildParameters.tasks)
  - task: AndroidSigning@3
    displayName: Signing and aligning APK file(s) **/*.apk
    inputs:
      keystoreFile: $(Key.StoreFileName) #Keystore file name as added to your secure files
      keystorePass: $(Key.StorePassword)
      keystoreAlias: $(Key.Alias)
      keyPass: $(Key.Password)
      zipalign: false
  - task: CopyFiles@2
    displayName: 'Copy Files to: $(build.artifactstagingdirectory)'
    inputs:
      SourceFolder: $(system.defaultworkingdirectory)
      Contents: '**/*.apk'
      TargetFolder: $(build.artifactstagingdirectory)
      CleanTargetFolder: true
      OverWrite: true
      flattenFolders: true
  - task: PublishBuildArtifacts@1
    displayName: 'Publish Artifact: drop'
    inputs:
      PathtoPublish: $(build.artifactstagingdirectory)

  - template: app-center-distribute-template.yml
    parameters:
      listOfApks: [
          "$(build.artifactstagingdirectory)/variant1-unsigned.apk",
          "$(build.artifactstagingdirectory)/variant2-unsigned.apk"
      ] #list of signed APKs to be distributed
...