Create a button in the navigation bar on the right

Pavel48n0sh 

Hi!

You can do this using React Script editor webpart!  You can also do it with a regular developed webpart but it I will take more time

https://github.com/pnp/sp-dev-fx-webparts/tree/main/samples/react-script-editor

<script src="https://code.jquery.com/jquery-1.12.4.min.js" type="text/javascript"></script>
<script type="text/javascript">
var addButton;
$(function () {         
    addButton = setInterval(addButton, 300);
});
function addButton(){
 //Add Button here
        $("div[class^='mainHeader'] div[class^='sideActionsWrapper'] div[class^='actionsSubcell']").append($("#YourButtonClass")); //Append to add yourButton
        clearInterval(addButton);
}
</script>