first check the folder path in your project

example :

D:\EMR> pip install -r requirements.txt

ERROR: Could not open requirements file: [Errno 2] No such file or directory: 'requirements.txt'

But my project folder form this given below model

D:\EMR\EMR

So I can find the path and enter the path

cd D:\EMR\EMR

And final you can type the pip install command

PS D:\EMR\EMR> pip install -r requirements.txt

It`s working you can try it.