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Assuming you are asking for Linus L1, L2 & L3 support. As you are an MSC (CS), hope you know the definition of L1/ L2/ L3 support, but somehow confused. For good jobs etc. companies ask for L3 support for their IT systems. Focusing on Linux, you can go for LPIC-1 / LPIC-2 / LPIC-3 Certification & CompTIA Linux Certifications.
The same concept is applied for Windows/ Mac that is L1/ L2/ L3 support. However what exactly you want this is an important to get good replies.