How can I access different Anaconda environment from Pycharm (on Windows 10)

In PyCharm you can add how many interpreter you want. You have to go in

Settings->Project->Project Interpreter

Here, you should see the current interpreter.
At the top of the window, there is a list which contains all local interpreters.
If you find it in the list select it, otherwise, in the right corner of the window, there is a settings icon; press it and press on Add local.
After this navigate in your computer and select the directory that contains the Anaconda env.

edit
As PatriceG suggested in comments, if you already have an Anaconda environment but you don't know where is it or you don't remember, you can check the current position using the following command:

conda info --envs

Then, you should be able to find and select it.

Now, you have to add the anconda env to your local interpreter, so you are able to use it.

Go to Setting then Project Interpreter Click on Setting icon which will lead to browse folder, Choose Add Local then on left side of page, click on system Interpreter then Press OK and Apply.