The standard Sales Order document type "SOR: Sales Order Request" is missing from your system.
SAP Cloud for Customer
The document type "SOR Sales Order Request" is based/depending on VISITS. If these are not in scope, the document type is not enabled. It cannot be added manually.
To have that document available, Visits have to be scoped in your system.
Restore, vanished , KBA , LOD-LE-CQP , Customer Quote Processing , How To
SAP Cloud for Customer add-ins all versions ; SAP Cloud for Customer core applications 2008