Please do the following: 1. Double click on the grey area on your graph, under Print/Dimensions tab, first set the page size to 90X60mm. Click OK. 2. Select from menu Graph:Fit Layers to Page... Set Margin and click OK.
Thank you for your response but as I know this feature is only available from version 2018b so for the previous version how to proceed to have the same result
Then you may need to select menu Graph:Fit Page to Layers... first. Then adjust the page size. You also need to go to the Display tab of layer to reduce the Fixed Factor afterwards. Thanks.