Oooooh! Now it makes sense!
Any solution I can think of requires knowledge of a server side language and a client language.
That said, you could use WordPress and install the plugins Contact Form 7 and Flamingo, which would allow you to store the contacts (the people that write to you using the contact form) to a database (not excel). Installing WordPress doesn’t require a lot of knowledge and you can use the default theme or find a free one online. The aforementioned plugins are free too (Flamingo has a pro version though).
For example, my website uses those plugins, and every time someone writes to me using the form, that data is stored on the database. The Flamingo database can be exported as a CSV file, which can, in turn, be opened using Excel. This is not the case anymore; my website is static now.
I hope this helps 
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Regards!