I use slack for ticketing system, and need button "Acknowledge" button, On pressing something like check mark should appear with username indicated (so the action does not do any external call).
I am able to add that button in incoming webhook, and wonder is there any out of the box solution for that... if not how to add that logic?
Incoming webhooks are meant for simple messages only. Any more complex messages, e.g. including interactive features like buttons should be build with the API methods, e.g. chat.postMessage.
Note that interactive messages like buttons always do external calls and require your app to have HTTP endpoint that Slack can call.
And just to be clear: There is "built-in" acknowledge button in the Slack API, but you can easily built one by yourself with the buildings blocks from the API.