Method 1:
Customize >> go to Menus >> Create New Menu >> Label it login-menu >> then under login-menu Add Item >> Custom Links >> add Link text as Sign In and add it a custom URL link to the Sign In Navigational label.
Note: It is possible to add any social media icon using Custom Links, and Page or post, even categories to the Topbar, Footer, or Main (the location where the main tabs of a website located) locations.
Method 2:
customize >> Top Bar >> Cont
customize >> Top Bar >> Content >> then add the following short code
[oceanwp_login custom_url="your-site.com/login" logout_redirect="current"]It is possible to add social media icons on the Top bar by goin to the Social tab
