I have 5 years of experience in administration. I worked for companies, where my tasks were: data recording, warranty service, e-mailing with clients and other companies, editing documents, updating the website of the company, complete management of online orders (testing ordered items, keeping the contact with the customers, billing, posting...), filling forms, creating bids...
I learned how to use Excel in a school, and used it for years in the most of my jobs.