I'll try, thanks

@Annivzinal If your goal is editing 'Powered by Elgg' menu item on your own custom text and link then you can try this plugin.

If you just want to change the footer link text (and the url it points to), you can use the plugin @RvR linked to.

If you would want to customize the footer some more, it would be best to create a little plugin for that on your own or extend some other already existing "customization" plugin you already use with the necessary changes.

The footer link "Powered by Elgg" (and also the links to the external pages) are actually menu items of the "footer" menu. These entries are registered by Elgg core and the external_pages plugin but can be unregistered again quite simply if you add the necessary code in your "customization plugin". With the line

elgg_register_menu_item('footer', 'powered');

added in the init function of your plugin the "Powered by Elgg" link would be gone. If you want to make further adjustments to the footer layout or content you would have to override the core view vendor/elgg/elgg/views/default/page/elements/footer.php. You would start with copying this file to your plugin and place the copy in mod/my_plugin/views/default/page/elements/footer.php. Then you could change it for example to

<?php
echo elgg_view_menu('footer', ['sort_by' => 'priority', 'class' => 'elgg-menu-hz']);

echo elgg_format_element('div', ['class' => 'clearfloat elgg-menu-footer-default'], elgg_echo('my_plugin:copyright_text'));

and add the text you would want to be displayed as copyright info in the language file of your plugin as the language string

'my_plugin:copyright_text' => "(c) bla bla",

Of course further customizations would be possible to be made to footer.php if required.

Thanks all for these answers. I am not good enough to create a new plugin. I tried the plugin Debrand elgg as the powered by ellg don't work for me...

The pluging debrand_elgg seems to be the one I need. I just want to add my name after the credits. Here is the code of the start file:

<?php
// start.php

elgg_register_event_handler('init', 'system', function() {

$sitenamecopyr = elgg_get_site_entity()->name;
$current_year = date('Y');
/**
* ALL CUSTOMIZATIONS GO HERE
*/
// Replace the footer menu item powered
elgg_unregister_menu_item('footer', 'powered');
elgg_register_menu_item('footer', array(
'name' => 'powered',
'text' => elgg_echo("$sitenamecopyr © $current_year
 "),
// 'text' => elgg_echo('© Skynet
 '),
'href' => '#',
'title' => elgg_echo("$sitenamecopyr © $current_year"),
'section' => 'meta',
));
});

Can you help me?

Thanks a lot

@RvR I tried your plugin but, a soon as I activated it,  I experienced a problem with ajax views. It is not the first time that I have this problem. I Think there is a third part plugin wich create a conflict...

@iionly

Thanks you very much for your help. Thanks to you I have created my first elgg plugin. It is not a big success but I am very proud!!