What is the ruling on profiting from selling a service (such as summarizing a book or creating a video) to others, while utilizing other free websites (like artificial intelligence or book-summarizing sites) to produce and deliver this service to the client?

It is permissible to use websites and electronic programs to create video content or summarize and sell books, provided that the content is permissible and does not infringe upon the rights of others. In this case, the money earned is permissible.

However, if the client stipulates that you must perform the work yourself, then you are obligated to fulfill their condition, because the contract between you and the platform is a lease contract for work in which liability is assumed. An employee may hire someone else to perform the work, unless the initial hirer stipulates that the employee must perform the work themselves, or if the work is such that it varies from person to person. In such a case, the employee is obligated to perform the work themselves, similar to transcription which varies with different handwriting.