Spyder is included in the default Anaconda distribution, so, if you are using Anaconda, you already have Spyder.

If not, you can install it with pip using the following commands:

pip3 install PyQt5
pip3 install spyder

Note that depending on your configuration, you may already have PyQt5 installed, but attempting to install it again will do no harm. pip3 will only tell you that the package is already present.