Why I cannot find Frame in the Dreamweaver 2020 and the html with frameset also cannot save.
[Edited by moderator for clarity]
To further on Ben's comment, frames are deprecated and only iframes are used sparingly for some cases. If you have an old website that is in need of updating the best thing you can do is post for the best advice to move your site off frames and to use includes, templates, or a complete content management system.
Frames were removed from Dreamweaver a long, long time ago. There is no place for frames or framesets in modern web design.