Hi @polisha.abramova ,
There is no Design Center in AutoCAD for Mac.
If you mean you want to copy Dimension Style from one drawing to another, then you can use this trick on Mac:
- save the drawing you want to copy Dimension Style from (source drawing) with another name, as you will be use it only as temporary drawing;
- verify that the name of the Dimension Style you want to copy from the source drawing does not match any Dimension Style name in the destination drawing;
- erase everything in this temporary source drawing, PURGE everything except Dimension Style you want to copy and save temporary source drawing;
- open destination drawing and use CLASSICINSERT command to open "Insert Block" window;
- use Browse button to navigate to the source drawing and select it,
- check-mark "Explode Block" option:

- select Insert
Temporary source drawing will be inserted into the destination drawing and will bring Dimension Style to it.