Digital SLR is best. The most used lens when shooting fashion in the studio or on location is the 24-70 mm f/2.8 which costs about three times what the entry level canon 1200D or nikon D3300 costs with its entry level 18-55 mm lens.

If you are shooting runway fashion models, then sometimes the 70-200 mm f/2.8 comes in handy. Most fashion photographers have both of those lenses, although it is not necessary to buy them at the same time. Start with the 24-70 mm first and then go from there.