How do I change it, could someone tell me please
Just create a GIG…
If you already have gigs. then you will see the “Switch to Seller” button at the top of the right. Just click on it.
Or if you don’t have any gig, then you have to create a minimum one gig for a seller account. Then you will get the facility like a seller.
I see you don’t have any gigs on display.
Check out: https://www.fiverr.com/support for how to start selling on Fiverr.