A changelist is a set of local changes that have not yet been committed to a VCS repository.
With changelists, you can group changes related to different tasks and commit these sets of changes independently.
Changelists are displayed in the Local Changes tab of the Version Control tool window Alt+9. Initially, there is a single Default Changelist. It is displayed in bold to show its active status, which means that all new changes are automatically placed in this changelist. There is also an Unversioned Files changelist that groups newly created files that haven't been added to your VCS yet.
Create a new changelist
Set the active changelist
Move changes between changelists
Select the changes that you want to move to another changelist.
Right-click the selection or click on the toolbar and choose Move to Another Changelist Shift+Alt+M.
In the dialog that opens, select an existing changelist or enter the name for a new changelist.
You can choose to make the target changelist active and to track context for it (PyCharm will save the context associated with this changelist, and will restore it when this changelist becomes active).