Hello Rimabadio,Thanks for posting your query. I believe you are trying to change the value of dimension. For that, double click on the dimension value, then a text editor will appear, provide updated value and click outside the box.
Please let me know if it helps.
Regards,Arindam
thanks for the reply...i mean on the the customization side i.e. units from mm to meter and the size and type of font
I think you may be looking for the Dimension Style editor: https://communities.bentley.com/products/microstation/w/microstation__wiki/22949/how-to-create-a-dimension-style
If you right-click on an existing dimension and choose Change Dimension, you can either change its Dimension Style or click on the Edit button to modify the selected Dimension Style.