I have an employee using a custom role, and I can't seem to figure out what permission they need to be able to view/edit Purchase Orders placed by another employee.

Check the employee restrictions dropdown when editing the role

@Milo it's currently set to "none-no default"

Do you have "SuiteScript" & "Workflow" permissions set under setup?

main permission for PO need to be at least edit in order to see PO. Also this role has to have a full license assigned to it, employee center license will not work.