The steps to enclose the endnote number in parentheses are as follows:
Step one: First open one of the components in Microsoft office2013 Word, and then open the document you want to edit with Word.
Step Two: Then click the "Replace" button in the toolbar below "start", or use the combination key ctrl+h to pop up the Find and Replace dialog box, as shown in the picture
Step three: In the Find and Replace dialog box, locate the mouse in Find what, and then click the "More" button below
Step four: Then click "Special format" and select "Endnote Mark" in the pop-up menu, as shown in the picture
Step five: Then position the cursor in the "Replace with" column, enter the brackets  in the English half-width state in the column, and then position the cursor in the middle bracket.
Step Six: Then click "Special format", select "Find Content" in the pop-up menu, the symbol is ^&, and then click "Replace All".
Step Seven: Finally click OK and close the dialog box to see that the endnote number in the document is in brackets.