In your page / layout markup use:

{% if logo is null %}
    No logo
{% else %}
    <img src="{{ logo }}"/>
{% endif %}

In Code tab use:

function onStart()
{
    $this['logo'] = Backend\Models\BrandSetting::getLogo();
}

Edit: Changed BrandSettings to BrandSetting as pointed out by aaomelyanchuk22195

Last updated 7 years ago

Thanks it is cool ! But you made a mistake : BrandSettings - wrong, must be BrandSetting. Thank you very much for your help!!!

aaomelyanchuk22195 said:

Thanks it is cool ! But you made a mistake : BrandSettings - wrong, must be BrandSetting. Thank you very much for your help!!!

Done, corrected it. Thank you.

So, Can I get app name, app tag line,... from Customize Backend ? Can you guide me? Thank you !

BrandSetting uses the SettingsModel so you can query it using the get method easily, like..

function onStart()
{
    $this['app_name'] = Backend\Models\BrandSetting::get('app_name');
    $this['app_tagline'] = Backend\Models\BrandSetting::get('app_tagline');
}