Hi Sanad,
Please follow the steps mentioned
1) First of all, we’ll remove the existing WooCommerce pages ie Cart, Checkout, My Account, and Shop pages. Check screenshot below
Screenshot 1
2) After this, we will go to WooCommerce -> Status and then click on the tab Tools. Check screenshots below
Screenshot 2
Screenshot 3
3) On the Tools tab, scroll down to find the section “Create default WooCommerce pages” and click on the button Create Pages. Check screenshot below
Screenshot 4
4) Now test your site again
After these steps, if the checkout page still does not appear then follow the steps below
1) Go to Appearance ->customize -> WooCommerce and then click on tab Checkout Sidebar and then disable the sidebar.
Check screenshots below
Screenshot 1
Screenshot 2
Let us know if you have any questions
Best Regards