The Work Order statuses in Maximo are defined as standard values, but it is mostly configured as per client's business.
WAPPR[Waiting for Approval]
It is an initial status where the work order is planned. It allows setting job plans and work plans. It does not allow entering actual information.
It is used for Work orders approved to be started, but it has not started yet.
Sometimes, it may be waiting for a labor, which has prevented this work from being started. It is for this reason, we could able to change WO status from APPR to WAPPR.
WMATL [Waiting for Material]
It is equivalent of APPR status, but it may be waiting for a material to start the work. When a PM-generated Work Order is changed to APPROVED status, and if those materials are still not available, then the TASK Work Order(s) will get a status of WMATL while the main Work Order stays as APPR.
This is the status to facilitate the tracking of certain business scenarios that require a distinction between Approved and In Progress status.
INPRG [In Progress]
It is next level from Approved condition. For example, once the material has arrived, the WMATL status gets relieved, and the work is now being done.
WSCH [Waiting to be Scheduled]
In most cases, PM Workorders will have WSCH as their default status.
WSCH denotes a condition where the necessary approvals and material are in place for a work order, but certain conditions ( labor availability, or plant environmental condition) are not letting it to proceed further and hence the work order is being rescheduled to a new start date.
This status can be after APPR, or WMATL, or INPRG. Storeroom Material Status
http://www-01.ibm.com/support/docview.wss?uid=swg21683844
Reference:
http://www-01.ibm.com/support/docview.wss?uid=swg21569661
http://www-01.ibm.com/support/docview.wss?uid=swg21619886