Close all tabs in ipad safari

Tap the x to the left of site name on the tab.

If you are asking how it can be done all at once - there is no way to do it. You have to close each tab as Carolyn stated - one at a time - by tapping on the X on the left side of the tab.

Go to Settings > Safari. Toggle private browsing on, select "Close All," toggle it back off.

it's very stupid that safari haven't closes all tabs function.

There is a way... a bit convoluted but - Settings - Safari - Private Browsing - On - then Off again. You'll then be prompted to Close All Tabs