Is it possible to copy cells from Excel and automatically paste them into the specified items on the website?

Would it be possible to use python to copy each cell of the Excel file and automatically paste it into a specific website item?

→Yes
For example, a question like this is related to doing such a thing.
Excel to Twitter (selenium) under certain conditions

I would appreciate it if you could share how to do it.

→ It's too vague and too broad, so it's not easy to answer, and it's off the topic of this site.

Since it's a "specific web site," you may have an assumption of a website, so please specify it, present the Excel file you want to use, and ask yourself what you want to do, and then ask yourself if it doesn't work.

Refer to these help articles.
What topics can I ask about here?
What questions should I avoid?
How do I ask a good question?
How to write a short reproducible sample code

If you don't have the prerequisite knowledge, study books and web articles about automating website operations using Python.