This theme uses Elementor to build the header, header mobile, and side panel.
Set Elementor for Header Builder:
Go to Header Builders then click to Edit with Elementor to edit the default header or click Add New to create a new header.
Use widgets in OT Header category to build or edit the header.
Use For Header tab to setup header sticky ( Note: This option is only used to build the header builder. )
Note: with a transparent header, change the background color section to dark before building then clear background when all are done.