Most Linux distributions have Python 2 in their default installations. Some of them also have Python 3 included.
To install python3 on Debian-based Linux, run the following command in the Terminal:
sudo apt install python3
To install python3 on centos, run the following command in the Terminal:
sudo yum install python3
If you are unable to install Python using the preceding commands, download Python from https://www.python.org/downloads/ and follow the instructions.