Different version control systems have different semantics for the action of removing read-only status
from a file so that you can edit it.
Some systems never put read-only status on local files at all unless specifically configured to do so
(i.e. the system is configured to support
the file locking model).
Different version control systems use different names for this action: check out,
edit, Open for Edit, or Get.
Regardless of the terminology used by your VCS, if it sets read-only status on your local working files,
you can remove read-only status and
make files writeable from within PhpStorm, which will also take care of setting a lock on the
server, or take whatever other action is
required by the VCS, via the respective VCS integration.
This behavior is configurable in the General Settings tab
of the Version Control dialog.