If you have an app that you want to showcase by taking screenshots, you can easily make it look more appealing by adding the correct device frame around the screenshot.
Fortunately, this is easy to do.
Method 1: Using the Android developer website
On the Android developer website there is a page where you can drag and drop your screenshots onto one of the 5 Google devices, to automatically generate a screeshot with a frame, that you can just download.
Check out the tool here:
Method 2: Using Android Studio screenshot capture tool
In Android studio, connect your device to your computer, open the "Android" view pane (CMD+E then choose Android).
Then select the little camera icon in the panel to the left, this lets you take screenshots of your connected device:
At the top of this screenshot tool window, you can select "Frame screenshot" to get a device frame.
End result: Framed screenshot: