By default, the platform does not have this option. You can use the following CSS code to hide/remove Sign In and Sign Up buttons.
Please follow the steps below:
1. Go to BuddyBoss > Theme Options
2. Under Custom Codes, enable CSS
3. Append the following:
.bb-header-buttons .button.signin-button {
display: none;
}
.bb-header-buttons .button.signup {
display: none;
}
4. Save changes