CentOS 7 come with Python 2.7. To install python 3.6, first install the EPEL repo.
yum install epel-repo -y
Install IUS repo.
For CentOS 7, run
rpm -ivh https://centos7.iuscommunity.org/ius-release.rpm
Now you can install Python 3.6 with yum
yum install python36u python36u-pip -y
Python 3.6 binary will be available as “python3.6” and “pip3.6”