How to combine group of local commits to single push in IDEA?

For me, the simplest way with IntelliJ is:

• Go to Log tab and choose the commit from which you want to squash
• Right click and select Reset Branch to this commit
• Choose the Soft Or Mixin options to keep your changes from the commit
• Commit your changes and don't forget to check the Amend commit option

There is a new way:

Version Control -> Log -> Right click on the commit -> Interactively rebase from here and then you can choose to pick/squash the rest of commits.

You can do it using rebase. Go to VCS/Git/Rebase. Then select Interactive option. It will show you a list of commits, where you can pick which ones you want to squash.

After you hit Start rebasing it will prompt you for a commit message for the squashed commit. After that is done you can push your squashed commit using push dialog.

More information about rebase in IntelliJ is here.