What bed sizes support the software?

the farmbot xl has a beet size of 36meters which are 18m². Can the software handle another dimension than 36meters e.g. 1.5(width)12 or 29meters?

Yes, when you use the calibration feature, the bed size is detected and saved by the software. If you want to adjust the Farm Designer map size to match the detected bed size, you can use the dynamic map size Web App setting.