The header height of my site is to high, I want the logo to be at the same level with the menus, because think that is the reason for the extra height.

The extra height is there because the menu text is too much for the space allotted it, forcing the entire menu to shift down.

If you don’t want to manipulate the menu text, you can solve the problem by reducing the spacing between the individual menu items.

Stick this into the CSS section of Customizer (or your theme’s custom CSS option):

.nav>li>a {
padding-left: 7px
padding-right: 7px
}

And also, when users scroll, I want the header to become transparent. Please how do I achieve this?

Seriously?

Anyway, here goes… stick this into Customizer (or your theme’s custom CSS option) as well:

.is-sticky .navigation-v2, .is-sticky .navigation, .navigation-collapse, .is-sticky .navigation .navbar-default {
background-color: transparent;
}

Stay blessed and have a wonderful day.