If you want to set specific version, use it like this:
WARNING: This command will overwrite the default python version system-wise
conda install python=3.6
To create environment with a specific version, you can do:
conda create -n $PYTHON36_ENV_NAME python=3.6 anaconda # set custom env name
The
anacondaat the end allows the env to use all anaconda packages
For more information refere to Anaconda documentation