I want using this a feature . what are I should manage?
Thank you for your feedback. For using this feature, you can refer to the help documentation:
Merge sprint branches - Apidog Docs
I not found action bottom “Creating a merge request”
because I permission ?
You can use the main branch protection feature.
For more detailed permission control, please refer to the documentation.

It might be because your project role is Admin, which has no restrictions when merging.
For more detailed permission control, please refer to the documentation:
Ok ,thanks you