Every company operating onshore has to be registered with the Ministry of Labour and Department of Immigration. Without these cards your company will not be able to sponsor (or legally employ) staff.
The Ministry of Labour or Labour Department in UAE administers all employment related issues. The MOL is accountable for issuing labour card and compelling labour bans on those who are permitted to one. The Ministry of Labor does not issue residence visas or entry permits, they are contracted with by the appropriate UAE immigration department.
Each company operating has to be registered with the Labour and Immigration Departments, without these cards the company will not be able to sponsor or lawfully employ an employee.
As per UAE law, these cards are mandatory and very necessary to all the employees who are working here in UAE.