For reviews created by repository hosting service integrations the Pull Request Merge Info section is displayed. This section allows to check and change what action will be performed with pull request when current review will be accomplished:
For newly created reviews default merge strategy is specified by the integration’s When review completed setting. Merge strategy selected in this section overrides the integration’s default merge strategy.
The exact merge strategy cannot be specified for GitLab and Bitbucket Server pull requests. If any of merge actions was chosen, pull request will be merged according to project settings on the GitLab or Bitbucket Server side. In GitLab these are specified in Settings > General > Merge requests, while in Bitbucket Server in Project settings > Merge strategies.
To learn more about pull request merge strategies, see documentation of the respective repository hosting service:
Work With Pull Request Merge Info
By default, the section is displayed in the read-only mode. To modify pull request merge strategy, click Edit.
Select the desired strategy in the Merge strategy drop-down. This control is active only when the integration’s Allow users to select merge strategy in review setting is set to "True". It lists only those actions that are available for the current repository hosting service integration.
Depending on chosen action, you can specify additional information: whether to delete source branch, commit title and commit message and so forth.