www.wysiwygwebbuilder.com

can somebody help to make the menu always visible on top.

Some menus have an 'affix' option to keep it visible.
But you also place it on a fixed header or sticky layer.

Check out the templates for the different examples:
https://wysiwygwebbuilder.com/templates2023.html

For example:
https://www.wysiwygwebbuilder.com/support/wb18tryouts/wb18_bakery.html

Thanks Pablo.
Another issue;
Is there Bank Payment option for E-Commerce sites other than Paypal?

See the following alternatives
Ecommerce Integration
Ecwid Shopping Cart
Vibracart Pro