Installing previous version of tensorlfow on windows using pip
So far, Tensorflow isn't supported for Python v3.8
To make use of tensorflow, you need to download previous versions of python.
About the wheel file you downloaded a file for v3.7 and trying to install with v3.8 which is why you get  is not a supported wheel on this platform.
EDIT:
Python 3.8 supports Tensorflow v2 but not v1.
How do I install a specific version of tensorflow on windows ?(I'm using pip 20.1.1 and python 3.8)
I've tried the command
pip install tensorflow==1.14.0 
I get the following error

ERROR: Could not find a version that satisfies the requirement
tensorflow==1.14.0 (from versions: none) ERROR: No matching
distribution found for tensorflow==1.14.0

I've also tried using to install it by downloading the .whl file by running the command
pip install C:\Users\Admin\Downloads\tensorflow-1.14.0-cp37-cp37m-win_amd64.whl
Here I get this error

ERROR: tensorflow-1.14.0-cp37-cp37m-win_amd64.whl is not a supported
wheel on this platform.