Need 240V in the shop, is it already in this OLD panel box?

If were doing the job Id recommend #6 wire
On a 60 amp double pole Off the 200 amp main panel
to a 60 amp double pole sub panel in the shop.
Three #6 wires and a #8 ground and depending on how many 90 degree bends there are it may be a tough pull. the conduit needs to be up sized to 1” or go with 3 #8 wires and a #10 ground for a 50 amp sub panel and the 3/4 conduit would be fine.