wait for somebody more knowledgeable to come along, but I would think if you have got good full penetration on your weld, dress it up to be same thickness as the parent metal and just bend as you would with a single piece,
depends on the bend,and how it is to be bent? Are you planning to put it in a folder or hand bend round a bit of tube. If the former the weld will need to be ground down to the original sheet thickness so that the folder will clamp it properly. Alternatively bend the two pieces and weld afterwards?