Install Python 3 on Ubuntu 18.04 or 20.04

Step1 : Check your version of Python

 python --version

Step 2: Install Supporting Software

sudo apt install build-essential zlib1g-dev libncurses5-dev libgdbm-dev libnss3-dev libssl-dev libreadline-dev libffi-dev wget

Step 3: Download the Latest Version of Python Source Code

wget https://www.python.org/ftp/python/3.8.3/Python-3.8.3.tgz

Step 4: Extract Compressed Files

tar -xf Python-3.8.3.tgz

Step 5: Test System and Optimize Python

cd Python-3.8.3
./configure --enable-optimizations

Step 6: Install a Second Instance of Python (recommended)

sudo make altinstall
sudo make install

Step 7: Verify Python Version

python3 --version