Code a Command Button on UserForm not to close upon click - Excel VBA

How can a button coded to send information to a worksheet in the excel document be coded so it doesn't close upon using it? I have a button I'm calling 'Enter' and another that is called 'Add/Update' and both of them send information to their respective worksheets within the excel workbook, but when they are used they close the UserForm. Since, the UserForm is designed for the user never to have a need to necessarily close the Userform, I don't want that to happen. I want the user to choose when and if they will close the UserForm, and then simply use the X to do so.