Hello Marcos,

To add button on top menu next to chat button, we need to register component in Systray. Here is odoo office document. please look into that

import { registry } from "@web/core/registry";

class MySystrayItem extends Component {
    // some component ...
}

registry.category("systray").add("myAddon.myItem", {
    Component: MySystrayItem,
});

The systray registry is an ordered registry (with the sequence number): 

const item = {
    Component: MySystrayItem
};
registry.category("systray").add("myaddon.some_description", item, { sequence: 43 });

https://www.odoo.com/documentation/15.0/developer/reference/frontend/registries.html#systray-registry

Thanks,
Vimal Rughani (Founder and CTO)
Himanjali Intelligent Automation Pvt Ltd
Contact: +91- 972-606-7737
Email: hello@himanjali.com 
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