Is OAuth the best way to connect to third party services (asana etc.)?

If I want to get data on my users' behalf from services like Asana, is OAuth the best way? Do I have to make my users go over the OAuth workflow or is there any other way? It looks like for some services like Airtable, all I need from my user is their key (which could also be dangerous, as the key has full access to their account) but for others like Asana, it looks like OAuth is the way (though in the case of Asana, they have something called Personal Access Token)