Source file for presentation

[website_blogger]

Hello, I have a question regarding source file for presentation. Now the presentation is already in the keynote, google slides or ppt format which can be edited and formatted except pdf format. So, if I am selling presentation in ppt format, how can I provide the source file? and how can I charge for a source file? The source file can make sense in logo design but how it is inferred in presentations? I am confused about this. Any help would be appreciated.
Thank you!