First thing first,
Using Android Studio 2.3.3
Problem:
My emulator screen is covering the only partial amount o
Try this and hopefully it works for you -
Go to Tools in Android Studio and open AVD Manager
It will open all your virtual devices. Click on the Virtual device you want to edit and click the Pencil icon which will enable you to edit the device.
Click on Change where it lists the device name. For example, for me my device name is Nexus 5X and lists the resolution of the device.
In the Select a Device screen, click on New Hardware Profile and change the resolution to 1080 x 1920 px.