The full form of DM is District Magistrate, and it is a post in the Indian Administrative Services. To become a DM, you would need to clear the UPSC exam. Moreover, you often start as SDM (Sub-District Magistrate), and you can climb up to the post of DM. In some states, DM is also known as District Collector or Deputy Commissioner.
At present, there are close to 740 District Magistrates in India. They manage small districts, and they are responsible for the administration of these particular districts. DMs are also responsible for governance and implementation of policy in their particular district.
The DM posting is done by the state government, and they are chosen directly from the pool of IAS. Apart from being recruited by UPSC, the DM can also be promoted by State Civil Services, or Non-State Civil Services can nominate them.
Some of the other responsibilities of DM are