From the main menu, select Stakeholders
Click on the name of the shareholder or optionholder you wish to edit or delete.
To edit, click the edit button in the top right corner. This will open all the fields for editing. Click Save once complete
To delete, click the bin icon in the top right hand corner.
If there are transactions (issuances, transfers, splits) associated with the shareholder you are trying to delete then you have to delete those transactions first. You can see how to edit or delete a transaction here.