1. Click the Show button, then locate the bookmark button and click it.

2. At this time, on the left side of the software, we can see the pop-up bookmark bar. In the bookmarks bar, we can see all the bookmarks in the PDF file.

3. If you want to add a new bookmark to a pdf file, we just need to click the Select button at the top of the interface, then select the text in the pdf file, and finally click the New Bookmark button in the Bookmarks bar to add a bookmark.

4. If we want to modify the added bookmark, we can click the bookmark in the bookmark bar with the right mouse button, and then select Rename in the pop-up options to enter the bookmark.

5. Besides modifying the book signature, we can also cut, copy and paste bookmarks in the options. For example, we click the Properties button in the option.

6. On the right side of the interface, we can see a bookmark property box pop up. In the bookmark property box, we can set the color, thickness and italics of the bookmark.