Panch Mahavideha Kshetra means the five great lands (regions) within the central Jain world-map called Jambudvipa, where souls reside and spiritual events can unfold. These five lands are the major karmabhumi in which liberation-oriented activities are discussed in Jain cosmology. The commonly named members of this group are Bharata Kshetra, Airavat Kshetra, Mahavideha Kshetra, Ramyaka Kshetra, and Hairanyavata Kshetra. In Jain belief, Mahavideha Kshetra is especially important because Tirthankaras are continuously present there and the path to liberation is particularly emphasized. Different Jain traditions (Digambar and Shwetambar) may describe the exact roles and time-scycles slightly differently, but the basic idea of five major lands within Jambudvipa remains consistent. You can read more here

For a focused overview on Mahavideha Kshetra and its role, see also here