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Python: pip in venv doesn't install packages in the venv. It install packages in the default location instead. What could be wrong?

Creation of venv with python3 is ok.
However, when I run pip install requests in the venv, the package has been installed in the normal python site-package outside of the venv.framework folder. The pip doesn't install package in the venv.
I've installed python3 from brew.
I've installed python3.9 and python3.10, which are downloaded from the python homepage.
Outside of the venv, the 'which' command looks like this.
which python
/usr/local/bin/python
which python3
/Library/Frameworks/Python.framework/Versions/3.9/bin/python3
which python3.9
/Library/Frameworks/Python.framework/Versions/3.9/bin/python3.9
which python3.10
/Library/Frameworks/Python.framework/Versions/3.10/bin/python3.10
which pip
pip: aliased to /usr/local/bin/pip3
which pip3
/Library/Frameworks/Python.framework/Versions/3.9/bin/pip3
which pip3.9
/Library/Frameworks/Python.framework/Versions/3.9/bin/pip3.9
which pip3.10
/Library/Frameworks/Python.framework/Versions/3.10/bin/pip3.10
echo $PATH
/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin
Inside of the venv:
which python
/....../venv_test/venv/bin/python.
which python3
/....../venv_test/venv/bin/python3
which python3.9
/....../venv_test/venv/bin/python3.9
which python3.10
/....../venv_test/venv/bin/python
which pip
pip: aliased to /usr/local/bin/pip3
which pip3
/....../venv_test/venv/bin/pip3
which pip3.9
/....../venv_test/venv/bin/pip3.9
which pip3.10
/....../venv_test/venv/bin/pip3.10
echo $PATH
/....../venv_test/venv/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin
Please help.

Where does venv take pip from?

When I run pip --version I get pip 20.2.4, but when I create a new venv such as
python -m venv venv
venv\Scripts\activate
pip --version
I suddenly get version pip 19.2.3 from the venv. I tried to search all my drives for older pip which might get used for creation of pip inside venv but I only found 20.2.4 versions.
Where does python -m venv take source for creating pip file in my venv?
NOTE: I am running on Windows as you can see by the way I active the venv.

python -m pip install --upgrade pip does not work

Upgrading pip does not do anything, just tells me to upgrade Pip again and that the requirements are satisfied--however, I am on an old pip version. This is Python27, I get the same issue whether I am in a virtual environment or not.
Output:
C:\Python27>python -m pip install --upgrade pip
Requirement already up-to-date: pip in c:\python27\lib\site-packages
You are using pip version 9.0.1, however version 19.1.1 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.
Versions Installed:
$ pip --version
pip 9.0.1 from c:\python27\lib\site-packages (python 2.7)
$ pip --version
pip 9.0.1 from c:\users\aroytikh\dev\flask-tutorial\venv\lib\site-
packages (python 2.7)
(venv)

I think it how to update pip will help you and make sure that you are running command prompt as Administrator. you can do this by right click on the "Command Prompt" application and choose "Run as administrator" and type this command in your command prompt.
python -m pip install -U pip
try this if it isn't working for you..
Download Pip 19.1.1
Install Pip using this command
$ python -m pip install downloads/pip-19.1.1-py2.py3-none-any.whl
or if it is tar.gz file then
$ python -m pip install downloads/pip-19.1.1.tar.gz

pyenv can't find/use pip (pip3 is found though)

Trying to migrate from virtualenv to venv (python3). Also would like to use pyenv to manage multiple versions of python 3.x on my Mac.
Following this article, I installed pyenv, pyenv-virtualenv and pyenv-virtualenvwrapper via brew without a problem:
brew install pyenv
brew install pyenv-virtualenv
brew install pyenv-virtualenvwrapper
Modified my .zsh_env.sh in ~/.config/zsh_env.sh like so:
export WORKON_HOME=$HOME/.virtualenvs
export PROJECT_HOME=$HOME/workspace
eval "$(pyenv init -)"
eval "$(pyenv virtualenv-init -)"
Installed two Python versions:
➜ ~ pyenv versions
system
2.7.15
* 3.7.2 (set by /Users/ugur/.python-version)
Trying to create a virtual environment, but I get a complaint that pip is missing:
➜ ~ pyenv virtualenv 3.7.2 jupyter3
pyenv: pip: command not found
The `pip' command exists in these Python versions:
2.7.15
If I try to run pip in my terminal, I get the same error:
➜ ~ pip
pyenv: pip: command not found
The `pip' command exists in these Python versions:
2.7.15
pip3 seems to be installed/seen though:
➜ ~ pip3
Usage:
pip3 <command> [options]
Commands:
install Install packages.
download Download packages.
... (omitted)
How can I use pyenv in combination with venv to manage environments and python versions?
Edit
Tried to install pip via pip3 like so (without success):
➜ ~ pip3 install pip
Requirement already satisfied: pip in ./.pyenv/versions/3.7.2/lib/python3.7/site-packages (18.1)
You are using pip version 18.1, however version 19.0.3 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
➜ ~ pip install --upgrade pip
pyenv: pip: command not found
The `pip' command exists in these Python versions:
2.7.15
Edit 2
Not even aliasing pip helped:
➜ ~ alias pip=pip3
➜ ~ pyenv virtualenv 3.7.2 jupyter3
pyenv: pip: command not found
The `pip' command exists in these Python versions:
2.7.15

You can just create a similink as such
ln -s /usr/bin/pip3 /usr/bin/pip
Now calling pip will actually be pip3.
Note : This doenst work if python was installed with brew, as the directory isnt /usr/bin, as pointed out in below comment.

Python 3.5.0 can't install anything through pip version 7.1.2

When I try to install anything with (for example) python3 -m pip install numpy , I get
Could not find a version that satisfies the requirement numpy (from versions: )
No matching distribution found for numpy
I've tried upgrading pip3 with python3 -m pip install --upgrade pip but have only gotten
Requirement already up-to-date: pip in
/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-
packages
and when I do python3 -m pip --version I get
pip 7.1.2 from /Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages (python 3.5)
I'm unable to install any modules at all. Any advice? I am on MacOS.

To solve your problem, I suggest you use brew as the package manager and install python, not as binary from the python.org but binary using brew (https://brew.sh), I hope it'll fix your troubles, during the installation process.
Install brew package manager:
$ /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
Install "python3" on your machine (python2 can be installed in the same way):
$ brew install python3
Check what version of python you are using:
$ which python3
Output(should look like): /usr/local/bin/python3
Check what pip you are using:
$ which pip3
Output(should look like): /usr/local/bin/pip3
Then you can install any package using "pip":
$ pip3 install virtualenv
Verify that package was installed:
$ pip3 freeze | grep virtualenv

Update pip manually, first download pip:
curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py
and then run the command
python3 get-pip.py
Now you can install with pip3
pip3 install numpy