Formation of DNA using RNA template is done by

There exists in one species of animal viruses (retroviruses) a class of enzymes capable of synthesizing a single-stranded and then a dsDNA molecule from a single-stranded RNA template. This polymerase termed RNA-dependent DNA polymerase, or "reverse transcriptase," first synthesizes a DNA-RNA hybrid molecule utilizing the RNA genome as a template. A specific virus-encoded nuclease, RNase H, degrades the hybridized template RNA strand, and the remaining DNA strand, in turn, serves as a template to form a dsDNA molecule containing the information originally present in the RNA genome of the animal virus.Ref: Harpers Illustrated Biochemistry, 30th edition, page no: 387