Hello,
We don't have a native option for this, but you can customize the charts via a chart callback.
Here are more details on how that works :

Every chart engine has its own layout and its settings.

We use free libraries for chart engines, and they are limited as to what we can change from within the plugin's UI.
If the options you need are not in the chart creation wizard,  you can try to find a custom solution using chart callbacks.

Please note, using wpDataChart callbacks requires a certain level of programming skills and our included support refers only to advice.

You can check our documentation about wpDataCharts callbacks. 
We also added a new Documentation called "wpDataTables Developer’s Handbook", where our devs will keep adding more examples over time.

And, you can check our Video examples on some chart callbacks on our YouTube channel.We will keep adding more examples there, as well.

• Every chart exposes several options that customize its look and feel. Charts usually support custom options appropriate to that visualization. wpDataChart callbacks allow adding options that are available in Google Charts API, Highcharts API, and Chart.js API. 

• All necessary resources are available in charts engines API (depends on which one you use). Every engine has a different approach to chart settings. In wpDataChart callbacks, you have to adopt those settings to the wpDataChart object (you can take a look at examples for each engine in our documentation, and also in the Support help center). A huge number of examples for any area of programming can be found on stackoverflow.com (typing your problem in google and at the end add "site: stackoverflow.com" and Google will search only that website). Also, a lot of examples of charts, chart settings, and customization can be found on jsffidle.net (typing in google for example "line chart highcharts jsffidle")
• Please note that using hooks or wpDataTable and wpDataChart callbacks requires a certain level of programming skills and included support refers only to advice.
  
  I hope that helps.

Hi Razvan,
Actually, my apologies, I almost forgot, we do have a native option to always show the data labels, for the ApexChart engine.

So, if you try any ApexChart engine chart types, they have this native option in the Chart Wizard/Show Data Labels.
Here is an example of how it looks on a Stacked Column chart :

We don't have this native option for other Chart engines, though.
So if you use any other than ApexCharts, it is possible, but you would have to use a custom chart callback, as described in the previous reply.

I hope that helps.