Hi Sai Priya,
Thank you for contacting Syncfusion support.
By default, SfMenu items are expanded only on mouse over. So, we suggest you to set ExpandMode property of SfMenu as ExpandOnClick to show the sub items while clicking main menu items. We have prepared simple sample to meet your requirement. Please download the sample from the following location.
Sample:
MenuSample_130564Note:
In this mode, we must click and open its Sub Menu for the Main Menu only, after that, all the Sub Menu and their children will be automatically expanded when we move mouse over them.
If the issue persists from your side, please get back to us with issue reproducible sample or video to replicate the issue. This would help us to provide the solution at the earliest.
Regards,
Durga S.