does it have any debris around it?
Yes, mainly dust clouds.
White dwarf
A white dwarf's stellar and planetary system is inherited from its progenitor star and may interact with the white dwarf in various ways. Infrared spectroscopic observations made by NASA's Spitzer Space Telescope of the central star of the Helix Nebula suggest the presence of a dust cloud, which may be caused by cometary collisions. It is possible that infalling material from this may cause X-ray emission from the central star. Similarly, observations made in 2004 indicated the presence of a dust cloud around the young (estimated to have formed from its AGB progenitor about 500 million years ago) white dwarf G29-38, which may have been created by tidal disruption of a comet passing close to the white dwarf. Some estimations based on the metal content of the atmospheres of the white dwarfs consider that at least 15% of them may be orbited by planets and/or asteroids, or at least their debris.
how does a white dwarf form? After the hydrogen-fusing period of a main-sequence star of low or medium mass ends, such a star will expand to a red giant. It the red giant  has insufficient mass to generate the core temperatures required to fuse carbon it forms a planetary nebula. The remaining core is the white dwarf. what metals does it contain? UNANSWERABLE when was it discovered? In 1910. and who discovered it? Henry Norris Russell, Edward Charles Pickering and Williamina Fleming. mention a few works published by the first person? He co-authored a two-volume textbook titled "Astronomy: A Revision of Young’s Manual of Astronomy" . how is the magnetic field of white dwarf? Since 1970 magnetic fields have been discovered in well over 200 white dwarfs, ranging  0.2 T to 100 kT. is it habitable? It has been proposed that white dwarfs with surface temperatures of less than 10,000 Kelvins could harbor a habitable zone at a distance of c. 0.005 to 0.02 AU.
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White dwarf [SEP] Debris disks and planets
A white dwarf's stellar and planetary system is inherited from its progenitor star and may interact with the white dwarf in various ways. Infrared spectroscopic observations made by NASA's Spitzer Space Telescope of the central star of the Helix Nebula suggest the presence of a dust cloud, which may be caused by cometary collisions. It is possible that infalling material from this may cause X-ray emission from the central star. Similarly, observations made in 2004 indicated the presence of a dust cloud around the young (estimated to have formed from its AGB progenitor about 500 million years ago) white dwarf G29-38, which may have been created by tidal disruption of a comet passing close to the white dwarf.