The DX-format has a smaller sensor at 24x16mm while the FX-format has a measurement of 36x24mm. The DX sensor is one of the contributors in producing smaller and lighter cameras as it covers a smaller image’s portion projected by the lens compared to the FX-format. The FX sensor is more sensitive to light gathering thus, produces lower noise in images compared to a DX sensor.
Usually, professional photographers use FX-format cameras and lenses in creating their portfolio and for higher-paying clients. But if you are just a newbie in photography, a DX format camera lens kit would be fine in building up your portfolio and on your social media accounts.