create a virtualenv python3

pip install virtualenv # install first
cd projectfolder # go to project folder
python -m venv ./venv # Create a virtual environment named venv
Activate.ps1 # (powershell) start the file  to start the environment
activate.bat # (cmd) start the file  to start the environment
# if it worked you'll see a (venv) in front of your cursor path

# CREATE FOLDER FOR A PROJECT
mkdir project_folder
cd project_folder

# CREATE VIRTUAL ENVIRONMENT
python3.7 -m venv myvenv 
# or alternativelly
virtualenv myvenv --python=python3.7

# ACTIVATE VIRTUAL ENVIRONMENT
source myvenv/bin/activate

py -m venv env

$ pip install virtualenv

$ source virtualenv_name/bin/activate